The word “plastic” comes from the Greek word “Platicos” and is used to describe something that can be easily shaped.

The history of plastics is longer than you might___________ . In fact the first man-made plastic ever to appear on the market was made over a hundred years ago. It was called “celluloid（赛璐璐）”. It was discovered by ___________an English man and an American in the same year.___________ it was the Americans who first produced it on a large scale（规模）during the year 1860. Everybody was ___________by this new material which could be moulded（用模子做）into shapes and was so cheap to buy.

Poor young men working in cities with lots of smoke and dirt were ___________ to buy white celluloid collars （领子）. The collars were hard and uncomfortable but they did not have to be sent to wash. The poor young men could rub them clean every evening with soap and water! Poor mothers, who had not been able to afford toys for their children, were now able to buy them toys___________ of celluloid.

But celluloid had one very serious fault. It caught fire very easily. In fact it burned even more quickly than wood or cloth. There were many terrible accidents, particularly___________ children. For years scientists worked hard to find a better plastic material than celluloid. They had _________ success. Then in 1932 an American scientist called Baekeland produced a hard plastic material which did not burn. It became known as bakelite（酚醛塑料）. Other plastic materials like bakelite were also produced. They were used to make electrical fittings （配件）and plates and cups. Poor people liked them because they were both cheap and___________, but rich people disliked them because they were cheap, and because they could only be made ___________dark colors.

There was once a little boy with a bad temper (脾气). He often had fights with his friends. One day, his father gave him a bag of nails (钉子) and told him to hammer (敲) a nail into the fence every time he lost his temper. The boy listened to his father and did what his father told him to do.

The first day, the boy drove 17 nails into the fence. Then the number of nails became less and less in the following days. The boy found that it was easier to keep his temper than to drive the nails into the fence. Finally, the day came when the boy didn’t lose his temper at all. He told his father about it and his father asked him to pull out one nail each time he was able to keep his temper.

The days passed and the young boy was finally able to tell his father that all the nails were gone.The father took his son by the hand and led him to the fence. He said, “You have done well, son, but look at the holes in the fence. The fence will never be the same as it was before. When you say some words in anger, your bad temper will leave a scar just like the hole. Even if you say you’re sorry, the wound is still there. If you hurt a person with words, the wound is as bad as a physical one. Friends are rare jewels (稀有珍宝). They make you smile and feel happy. So never hurt your friends.”

Since then the boy had never fought with his friends. He learned how to get on with others and he never lost his temper again.

Self- reflection (反省) means stopping the mad rush of activity and keeping yourself and your mind cool, so your brain can evaluate (评价) the input that it has already received. Some people prefer to do their self-reflection in the way of thinking, while others do it in the way of writing something, like keeping a diary or writing notes of some kind.

School textbooks are often divided into units of study. This can make self-reflection easier for someone who wants to do it. Self-reflection can be done in any of the subjects you are learning: math, art or others. Sometimes you are reminded that the unit is over because there is some kind of test. Using those natural breaks above as chances to reflect is a good way.

As a student, you can do self-reflection at school. First, you can write down some notes on things that you learned in this unit that you did not know before you began. Let your mind think over the notes and make some connections with what you have learned. Next, think about the things that you still wonder about. For example, you learned a new way to solve a math problem, but you are not sure when to use it. Writing down your questions will help you remember to seek answers when you meet the same topic again.

Self-reflection is an important skill for a successful student. If you have never taken the time to reflect, try it now.

Do you believe that only boys do well in science? Does it seem to you that girls have better language skills than boys? In your opinion, are boys better at building things? If your answer to each of those questions is “Yes,” you are right, according to an article in Current Science." There are exceptions(例外), but here are the facts.

Usually, boys score higher on tests about math, while girls do better in tests about words, spelling and memory. But these differences may not always be true. In the future, a person’s abilities may not be decided by sex. As one scientist says, “Nothing is impossible for a person to be or do.”

A recent study by Jerome Kagan, a scientist at Harvard University is studying the watching ability of children 10 months old. Baby boys and baby girls are watching a “show” while seated on their mothers’ laps. In Act One of the show, an orange-colored ball is lifted from a blue box and moved slowly. Then it is returned to the box. This is repeated six times. Act Six is almost the same, except that the orange ball is smaller.

Baby boys do not seem to notice the difference in the size of the ball, but girls immediately become excited and begin to make noises that sound like language.

It’s also known that baby girls usually talk at an earlier age than baby boys do. Scientists believe that the left side of the brain develops faster in girls than in boys. As a result, by the time they start to school, little girls have an advantage that boys don’t have, but what have the boys been doing in the year before starting school? They have been developing something called aggression. An aggressive person feels strong and independent. He is often the first one to start a fight. It is said that aggression is caused by hormones (荷尔蒙). Scientists believe that hormones are not the only cause. They say aggression in boys is also caused by mothers.

Night Milk and Sleep

A warm drink of milk before bed has long been the best choice for those wanting a good night's sleep. But now a study has found it really does help people nod off-if it is milked from a Cow at night.

Researchers have discovered that “night milk” contains more melatonin（褪黑激素），which has been proven to help people feel sleepy and reduce anxiety.

The study，by researchers from Seoul，South Korea，involved mice being fed with dried milk powder made from cows' milk milked both during the day and at night. Those given night milk，which contained 10 times the amount of melatonin，were less active and less anxious than those fed with the milk collected during daytime， according to the study published in The Journal of Medicinal Food.

Night milk quickened the start of sleep and caused the mice to sleep longer.

While the effect of cows’ milk harvested at different time has not been tested on humans up to now，taking melatonin drugs has been suggested to those who are struggling to fall asleep at night.

Previous studies have also showed that milk can be excellent for helping sleep because of the calcium content，which helps people to relax.

Milk is also sugar-free and additive free with nutritionists recommending skimmed milk as the best choice before bed as it is the least fattening. The more fat you take in before bedtime, the greater burden you will put on your body at night.

When students leave junior high school, they are often    48    (worry) about moving to senior high school. It is a hard time for them, but it can be an exciting one as well.

To make it     49    (easy), students need to get familiar (熟悉的) with their new school. Most senior high schools have a freshman speech f    50    students. Sometimes the school office will give away a map of the school. It can help students and parents find different places in the school. O    51     way to know the senior high school better is    52    ( join) a club. And joining a club is also a good way to make new     53    (friend).   Senior high schools often    54    (offer) new students chances to join different clubs. There are many clubs, such as a chess club, a soccer club etc. Students from different grades are    55    (allow) to join these clubs. The school office will make     56    list of the clubs and give the information about how to join    57    (they).

63. 由于新型冠状病毒疫情影响, 多省市教育局发布了推迟开学的通知。最长寒假, 线上教学, 这对学生的饮食和学习状态都是一种考验。面对这次疫情, 你应该怎样正确对待?

Because of coronavirus(冠状病毒), we have been staying at home for nearly a month.

I hope everyone can be healthy and happy every day.