Scientists usually have to do thousands of     1    (experiment)in order to prove something new or true. They often fail,     2     they never give up.

My neighbour     3    (be)a scientist. He studies chemistry. He is always working alone in     4    (he)lab, trying to figure out all the mysteries that make him     5    (puzzle). One day, when I met him, he had just come back     6     work. Tired as he was, he     7    (sound)so excited. Then I noticed that he was wearing shoes     8     did not match. He must have been working too hard to notice that!

Now I have come to realize that it’s good for you     9    (do)a job that interests you. You will be absorbed in it, and push yourself hard with it     10    (happy).

4 . Tristin Stewart, 15, of Northern Ireland, has no right knee after undergoing an operation. Now, his right leg connects directly to a right foot backward, which fits more_______than a traditional amputation (截肢).

Tristin said he began experiencing_______in his right leg in 2014, but it was not until last year that doctors diagnosed it as a cancer. The diagnosis and_______operation made Tristin’s parents, Mandy and Shane so worried.

“Tristin was scared firstly before receiving the operation,” Mandy said. “When we went in to see him after the operation, you could_______see that something was not in the right place under the_______, and Shane and I got up the courage to uncover it. That was a very strange sight, but my boy’s life was saved so that’s all that_______.”

In spite of a_______disease, the first in Northern Ireland, the soccer-loving teen is already back on his_______ just months after the operation.

“At the start it was uncomfortable and I wasn’t used to it because of the weight and my foot — you know, it felt_______— but now I’ m accustomed to it,” Tristin told Caters News. “It feels close to normal.”

“I can________with it and I’ve just started a jog,” Tristin said. “Without it, I’d be in a________. I wouldn’t be able to do anything.”

Unexpectedly, many people are now________ money to buy Stewart professional aid equipment so he can________in sports and more physical activities.

“Friends have been just as________, and they haven’t treated me differently,” Tristin added. “And I believe no matter how________ the mountain, there will always be a climb for the people who do not fear the difficult.”

One day, Nick invited his friends to supper. He was cooking some delicious food in the kitchen. Suddenly, he    1    (find)that he had run out of salt. So Nick called to his son, "Go to the village and buy some salt, but pay a fair price for it: neither too much    2    too little. "

His son looked surprised. "I can understand why I shouldn't pay too much, Father, but if I can pay less,     3    not save a bit of money? "

"That would be a very    4    (reason)thing to do in a big city, but it could destroy a small village like ours," Nick said.

Nick's guests,     5    had heard their conversation, asked why they should not buy sale more cheaply if they could. Nick replied, "The only reason a man would sell sale    6    a lower price would be because he was desperate for money. And anyone who took advantage of that situation would be showing a lack of respect    7    the sweat and struggle of the man who worked very hard to produce it."

"But such a small thing couldn't    8    (possible)destroy a village."

"In the beginning, there was only    9    very small amount of unfairness in the world, but everyone added a little, always    10    (think)that it was only small and not very important, and look where we have ended up today. "

7 . A few years ago, I realized that I had a fear of heights. Sometimes I would feel uncomfortable if I looked down from somewhere high and the higher I got, the worse I felt. However, there were some things that made me nervous when I looked up at them — such as drop towers (急速下降塔).

About a month ago, my family and I went on a trip to Marineland — an amusement park with a sea animal theme. One of Marineland’s attractions is a huge drop tower called the “Sky Screamer”. My dad wanted to ride it, and he wanted to take me with him. He kept encouraging me, and I finally gave in, because I was desired to face my fears.

Going up was terrible. I got stomachaches from just looking at the tower. When we reached the tower, we lined up and got seated on the ride. When it reached a few feet off the ground, it stopped for a moment, before sending us straight to the top at great speed. I squeezed my eyes shut and I held the handlebar (把手) as tightly as I could during the whole ride. A few seconds later my heart was in my mouth and I was screaming my lungs out. At the top, I opened my eyes and looked forward, not down.

I tried to prepare myself for the way down, but it didn’t really help. There I was, with my eyes squeezed (紧紧地) shut, holding the handlebar and again, screaming at the top of my voice. In fact, it was even worse than going up! But when I got to the bottom, I felt relieved. I thanked my dad for forcing me to go on the ride, and I was pleased I had overcome my fears.

So, was the “Sky Screamer” scary? Well, maybe just a little bit.

After an exhausting swim practice on a cold winter evening, I received an invitation from my friend Lucy, asking me to attend a dance. At the top of the invitation, Young Angels was written across the page. Young Angels was organizing a dance to raise money for community service projects. I thought it was such a great idea that I not only wanted to attend it, but also wanted to become involved.

This was over two years ago and since then, I have become a lead member in Young Angels of America. At each dance, teens not only have fun with their friends but are also informed about different charities. Knowing that I have taught others how they can get involved makes me feel satisfied and delighted.

The most memorable experience of my time in Young Angels was the Middle School Winter Dance in 2007, when we had a special child help organize the dance and participate in the event. This child was Lily. Lily had a dreadful disease that will eventually kill her. Lily had the best attitude towards life: she enjoyed every moment and made the best of it. Lily got me inspired to help others and never take any moment for granted.

I now have a dream, I want to inspire as many children as possible to volunteer. So many kids don’t realize how easy it is to make a difference to the world. I am only 15 years old and I have organized over five events, getting nearly 1,000 children involved. I want to be the angel to inspire that passion in others to make the difference that I feel as I have made to my community.