One Monday morning, Paul and his classmates were in the science laboratory for their chemistry lesson. The students were going to work in pairs to do an experiment. Before they began, the teacher gave them this description of the different stages of the experiment.
Stage 1: Prepare the equipment: a test tube, a crucible(坩埚), a Bunsen burner(煤气灯)and tongs(钳子).
Stage 2: Weigh 5 grams of baking soda (小苏打) and put it in a crucible.
Stage 3: Heat 10 ml of hydrochloric acid (盐酸) in a test tube.
Stage 4: Pour the warm acid onto the baking soda and continue to heat the mixture.
Result: The acid reacts with the bicarbonate(碳酸氢盐)to form water, carbon dioxide gas and salt.
The hotter the mixture, the quicker the reaction. Continue to heat the mixture until the water evaporates(蒸发), leaving the salt in the crucible.
Paul and his partner followed the instructions and set up their equipment. Paul went to the cupboard to get a bottle of hydrochloric acid. He found that there was only one bottle in the cupboard so he took that. There was no label on the bottle and Paul didn’t check with the teacher if it was the right solution(溶液).
He measured the liquid and poured it into a test tube. Using tongs to hold the test tube, he heated it over the Bunsen burner. That’s when things started to go wrong. The liquid in the test tube was not hydrochloric acid. When it was heated, it formed a thick cloud of white gas. Soon the room was full of this strong smelling white gas.
All the students started coughing and their eyes hurt. The teacher immediately opened the windows and ordered the students to leave the laboratory at once. She realized that the liquid was acrylamide (丙烯酰胺) and that it is poisonous.
Fortunately, nobody was injured in the incident. However, it taught the students and the teacher a good lesson.
1. The teacher and her students planned to make ________ in the experiment.A.water | B.salt | C.acrylamide | D.carbon dioxide gas |
A.By putting more hydrochloric acid. | B.By heating the hydrochloric acid. |
C.By making the water cooler. | D.By making the mixture hotter. |
A.There was only one bottle. | B.His partner didn’t help him check it. |
C.There was no label on the bottle. | D.He didn’t pick the right one out of the bottles. |
A.His teacher ordered him to stop it at once. | B.The white poisonous gas was formed. |
C.All the students left the lab at once. | D.Someone was injured in the accident. |
A.Never leave a bottle without a label in the chemistry lab. |
B.Obey your teacher’s instructions in the chemistry lab. |
C.Acrylamide can’t take the place of hydrochloric acid. |
D.While something unusual happened, leave the lab at once. |
相似题推荐
【推荐1】Do you like to exercise? I think everyone likes to exercise, because it's good for studying.
The students in our school love to exercise.
Exercising can help us study better.
A.Basketball is our favorite. |
B.Everybody likes to relax more after work. |
C.Everybody knows exercising is important. |
D.So we can cut up more fruit for the salad. |
E.In every class there are a lot of volleyball fans. |
F.So we can get better grades after we get enough exercise. |
G.Every morning after we get up, we run, and then do morning exercises. |
【推荐2】Starting a volunteer club at school isn’t easy. But with good ideas and the right knowledge (知识), you can do it. Read on to learn how.
①_________ Decide what you want to do. For example, you can start a club to volunteer once a week at a soup kitchen in your neighborhood. Ask around and see what your friends think of your idea, and if they would like to join your club. When you have enough support (支持), you’re ready to start.
②_________ Because your volunteer club is at school, it’s better to get a teacher’s support. He or she can help you organize events and be a liaison (联系人) with the school.
③_________ After the school lets you start the club, you need a place to have meetings. Most clubs meet in classrooms after school. You can also think about meeting at someone’s house or at a park or restaurant.
④_________ Talk with other members (成员) and then choose a proper day when most members will be free.
⑤_________ Once you have enough members in your club, start volunteering! You can decide on events yourself, or have a meeting to get other members’ ideas.
It’s common to have some trouble when you start a volunteer club. But don’t give it up easily. You will have much fun in the end.
1. What does the writer think of starting a volunteer club?A.Easy. | B.Serious. | C.Impossible. | D.Difficult. |
A.Busy. | B.Special. | C.Right. | D.Meaningless. |
A.Decide when to have a meeting by yourself and then tell it to others. |
B.It’s useless for you to ask others’ ideas when you want to start a club. |
C.It’s best for you to have a meeting with other members in a classroom. |
D.You can ask the members’ ideas when you want to organize an event. |
a. Find a place.
b. Plan volunteer events.
c. Be sure that you really want to start a volunteer club.
d. Decide when to meet.
e. Ask a teacher for help.
A.①-a, ②-b, ③-c, ④-d, ⑤-e |
B.①-c, ②-e, ③-a, ④-d, ⑤-b |
C.①-b, ②-d, ③-c, ④-a, ⑤-e |
D.①-c, ②-b, ③-a, ④-d, ⑤-e |
A.Why we should start a volunteer club. | B.How to start a volunteer club. |
C.How to enjoy yourself in a club. | D.What to do in a volunteer club. |
He is 12 years old. He finishes school at half past three, so he has a lot of time to play sports. | A. English Corner Do you want to improve your English? Join our English comer. B. Sports Club Do you want to lose weight? Keep fit with us! C. Join Our Football Team Boys and girls, do you want to play football? Aged 9- 13. Meets in Green Park on Friday at 4 p.m. D. Room To Rent Small room to rent in city center flat(公寓) above restaurant. E. Big House For You A big house with 4 bedrooms and a big garden is on sale. Call at 67216625. F. Waitress Wanted For Busy Restaurant. Waitress. Some evening and weekend work. All meals free. Call at 3320178. G. Roommate Wanted Want a quiet man to share a house with two bedrooms. The house is quiet. It’s far from the streets and bus stations. |
Name | Time | Subject | Feeling(感觉) |
Bill | Monday 8:00-9:00 | Science | Difficult |
Jennifer | Wednesday 10:00-11:00 | Geography | Interesting |
Scott | Thursday 13:00-14:00 | English | Fun |
Selina | Friday 14:00-15:00 | Chinese | Boring |
1. When does Bill have science?
A.On Monday. | B.On Wednesday. |
C.On Thursday. | D.On Friday. |
A.Difficult. | B.Fun. | C.Boring. | D.Interesting. |
A.From 8:00-9:00. | B.From 10:00-11:00. |
C.From 14:00-15:00. | D.From 9:00-10:00. |
A.Bill. | B.Jennifer. | C.Scott. | D.Selina. |
A.Bill thinks science isn’t difficult. |
B.Scott has geography from 10:00 to 11:00. |
C.Selina has Chinese on Wednesday. |
D.Jennifer likes Geography. |
We usually get up at six o’clock in the morning. First,we do morning exercises for half an hour on the playground(操场).Then all the students and teachers have breakfast in the dining hall(食堂).After breakfast, I usually read English with my classmates in the classroom.
Of all the weekday,I like Thursday best,because I have a music lesson on Thursday. Music is my favorite subject. I usually have four lessons in the morning and three lessons in the aftermoon. But on Thursday aftemoon we only have two 1essons.
I like my classmates and teachers. My school life is very good.
1. LiLei’s school is __________.
A.big and nice | B.big and old | C.old and small |
A.6:00 | B.6:30 | C.7:00 |
A.does morning exercises | B.has a music lesson | C.reads English |
A.All the students and teachers live in school from Monday to Friday. |
B.Of all subjects, Li Lei likes English best. |
C.Thursday is Li Lei’s favorite day. |
A.five | B.six | C.seven |
Thanks for your letter. I’m glad you like your new school. I go to school from Monday to Friday. We have five classes in the morning and two in the afternoon. And we have many subjects to learn: Chinese, math, English, P. E., science, biology, music, history and so on. We also have many things to do after class. On Monday and Wednesday afternoons we play sports after class. On Tuesday afternoons some of us have a drawing class, and on Thursdays some have a dancing class. I like music, history and English. But my favorite is music.
On Saturdays and Sundays I don’t go to school. Usually I go to the park and have a good time with father and mother there.
I miss you so much, my dear sister! Please come back soon!
Yours,
Lin Fang
1. Lin Fang has _________ classes a day.A.five | B.two | C.seven | D.three |
A.play sports | B.have a drawing class |
C.have a dancing class | D.go to park |
A.music | B.English | C.history | D.P. E. |
A.Anna | B.her classmates | C.her parents | D.her teachers |
A.teacher | B.student | C.mother | D.sister |
【推荐1】Lucy Brown, aged 12, puts smiles on the faces of kids and keeps them very warm too. She sews(缝纫) blankets(毯子) for children who are dealing with challenges such as being sick, feeling unhappy, or losing a family member.
Lucy got the idea four years ago. She had just learned to sew and made a blanket as a gift for her friend’s birthday. “She loved it.” Lucy says “So, I thought maybe other kids might need that kind of love.”
Her mom posted(发布) on the Internet that Lucy wanted to make a blanket for someone who needed care. They collected the kids suggestions. When 20 suggestions came, Lucy didn’t just choose one. She met all of their needs! She has already made more than 800 blankets for kids in countries.
Her favorite part is learning about each child. “I love hearing their stories and getting to know them” she says. She tries to design styles according to the children’s interests. On each of the blanket, Lucy adds a hand-sewn(手工缝制的) heart, “That’s to let anyone who gets the blanket know they are loved,” she says.
Many kids who receive a blanket keep in touch with Lucy. She now has friends all over the world “I love knowing that I can make a difference.” Lucy says. “Everyone can do something. Even the smallest act of kindness can change lives.”
根据短文内容,选择正确答案。
1. How old did Lucy get the idea to sew blankets for other kids?
A.4 years old. | B.8 years old. | C.12 years old. | D.16 years old. |
A.Her mother. | B.Her father. | C.Her brother. | D.Her friend. |
A.Over 200 blankets. | B.Over 300 blankets. |
C.Over 800 blankets. | D.Over 900 blankets. |
A.To make some blankets. | B.To add a hand-sewn heart. |
C.To sew blankets for children. | D.The smallest act of kindness. |
A.Sewing the Blankets for Kids | B.Small Action, Big Love |
C.Mother Helps Daughter | D.Blankets and Lives |
【推荐2】Mr. White’s house is about 1.5 kilometers from his office, so he can drive home every day for lunch. Every time he drives home at noon, he finds many cars outside his house and there is no room for his own car. He has to drive to other places to park (停) his car. Then he walks back home. This makes him very angry.
He puts up a board facing the road. The board says, “No parking”. But no one notices (注意) it. People like to follow only a police notice (公告) with white letters on a blue board:
POLICE NOTICE NO PARKING |
Mrs. White asks her husband to steal (偷) a police notice but he is afraid to do so. Then she asks him to make one just like a police notice. Mr. White says he is not the police and can’t use the word “police”. Some days later, Mr. White makes a blue board with whiter letters.
POLITE NOTICE NO PARKING |
“Oh!” Mrs. White says, “You tell me you are not going to use the word ‘police’, but why do you use it now?” “Really?” he says, “look again.” She starts to say, “You are really clever.”
正确的填“A”,错误的填“B”。
1. Mr. White’s house is not far from his office.
2. Mr. White is unhappy because he finds no room to park his car outside his house.
3. Many people like to follow the first notice that Mr. White makes.
4. Mr. White makes three notice boards in all.
5. Mr. White is afraid to use the word “police”, so he doesn’t use it.
【推荐3】Long long ago, in the forest there lived a deer (鹿), a bird and a mouse. They were good friends. One day, a turtle (龟) came to them and said, “I’m all alone. I want to join your group and become your friend.” “You’re most welcome,” they said.
One day, when the four friends were playing, they saw a hunter (猎人) coming. The deer ran away into the forest. The bird flew high in the sky and the mouse ran into a hole. The turtle couldn’t run as fast as the others. The hunter caught it and put it in a bag. Then the hunter went home.
The deer, the mouse and the bird were worried about the turtle. ________
First, the bird flew high up in the sky and saw the hunter walking along the river. Then the deer lay on his way and didn’t move at all. It pretended that it was already dead (死的). When the hunter saw the deer again, he was very happy. He put the bag with the turtle inside on the ground and moved to the deer. As soon as the hunter left, the mouse opened the bag and freed the turtle. When the hunter reached the deer, it suddenly stood up and ran away.
The hunter could do nothing but turn back to pick up his bag. To his surprise, the bag was open and the turtle wasn’t there. He left the forest with nothing.
根据材料内容选择最佳答案。1. Who was the last one to join the group?
A.The deer. | B.The bird. | C.The mouse. | D.The turtle. |
A.They all liked the turtle. | B.But they were also in great danger. |
C.Together, they made a plan to save it. | D.They decided to ask others for help. |
A.尝试 | B.假装 | C.获悉 | D.解释 |
A.It made a hole. | B.It opened the bag. |
C.It found where the hunter was. | D.It asked the hunter to let it go. |
A.Being together makes a difference. | B.Helping others is helping yourself. |
C.Don’t be afraid when in danger. | D.Run fast when danger comes. |
【推荐1】When I was a little child, my mom sometimes liked to make breakfast food for dinner. And I remember one night she made breakfast after a long hard day at work.
That evening, my mom placed a plate of eggs, sausage and very burned (完全烤焦的) cookies in front of my dad. I remembered waiting to see if anyone would say anything. But all my dad did was to reach for his cookie, smile at my mom and ask me how my day was at school. I didn't remember what I told him that night. But I did remember watching him eat bite of that cookie!
When I got up from the table that evening, I remembered hearing my mom say sorry to my dad for burning the cookies. And I'll never forget what he said, “Dear, I love burned cookies.”
Late that night, I went to kiss Dad goodnight. And I asked him if he really did like his cookies burned. He gave me a big hug and said, “Your mom had a hard day at work today, and she's very tired. Besides, a little burned cookie never hurt anyone!”
Life is full of imperfect things and imperfect people. We need to learn to accept each other's faults(错误,过失) and celebrate each other's differences.
1. After the mom made dinner one night, the writer .A.showed no interest in the cookies his mom made |
B.was so hungry that he couldn't wait to eat all the food |
C.waited to see if his dad noticed the burned cookies |
D.talked about the fun things at school with his dad |
A.happy | B.angry | C.sad | D.crazy |
A.was deeply in love with his mother | B.was very busy during the daytime |
C.liked eating cookies very much | D.liked making dinner for his family |
A.Never hurt those who love you. | B.Be thankful for what you have today. |
C.Learn to be understanding. | D.Think twice before making a decision(决定). |
【推荐2】When you look at a giraffe, what do you see? A leopard’s coat? A camel’s head and neck? A cow’s feet? Or a sake’s tongue? Why does the giraffe have so many different characteristics (特征)? The giraffe needs all of them to survive (生存).
Giraffes have long necks for two reasons. First, they eat from the tops of very tall trees. Second, they need to see over the tops of the trees. They can see danger, like a lion, from far away. Then they have time to run away or hide.
The giraffe’s coat is also important to its survival. It has brown spots and is very thick. The spots help the giraffe hide among the trees. The giraffe’s thick coat protects it from the sun.
Two other important characteristics of the giraffe are is large eyes and long thick eyelashes. With its large eyes, it can see very well. The eyelashes protect its eyes. The giraffe sees better than most other large animals in Africa.
A giraffe’s hard feet and strong legs are also important for self-protection. If a lion comes too close, the giraffe can kick it on the head. That usually kills the lion.
One last characteristic is the giraffe’s long black tongue. It is about 18 inches long with their tongues, giraffes get food far above their heads. They also clean their eyes and ears with them. Why is the giraffe’s tongue black? The color protects it from the sun.
Maybe the giraffe looks like four animals. But of course we know it is not. It is one animal, with many characteristics. Its characteristics help it survive.
1. Which of the following characteristics for a giraffe to survive is NOT mentioned?A.Thick eyelashes. | B.Long neck. | C.Large ears. | D.Black tongue. |
A.Giraffes are so tall that they can't hide among the trees. |
B.Giraffes have thick coats to protect themselves from the sun. |
C.Giraffes have hard feet and strong legs to kill lions. |
D.Giraffes always clean their necks with their black tongues. |
A.giraffes | B.heads | C.tongues | D.colors |
A. | B. |
C. | D. |
Once upon a time, there were four seeds(种子) who were good friends. They travelled by wind and came to a forest. They hid themselves in the ground, and hoped that they would be able to grow into big trees.
But when the first seed began to grow, they realized it would not be such an easy task. There lived a group of monkeys, and the smallest monkeys loved to throw bananas at any plant that started to grow. They threw so many bananas at the first seed that she was almost cut into two. When she told the other seeds what happened, they thought that it would be better to wait until the monkeys went away.
They all agreed with that except the first seed. She thought she would at least try it. When she tried harder, she was hurt by bananas. The other seeds asked her to stop trying. But she had make up her mind to become a tree. She tried again and again. Every time she was hit by bananas, she would try harder. The scars(伤疤) left by the bananas helped her grow stronger than the other seeds. Later, she could withstand(经受住) the hit of the bananas. She had already grown so well that the monkeys couldn’t hurt her badly. At last, she grew into the biggest tree in the forest. The other seeds still hid themselves in the ground, hoping the monkeys would go away soon. That’s the way with a lot of things. The final victory always belongs to those who keep trying.
1. The seeds in the passage came to a forest because of a wind.2. The four friends hoped to grow into big trees with the help of the monkeys.
3. The monkeys in the forest all loved to throw bananas at plants.
4. Only the first seed tried her best to overcome difficulties to grow up.
5. The passage mainly tells us that we should keep trying to get what we want.