阅读下面短文，掌握其大意，然后在各题所给的四个选项（A、B、C和D）中选出一个最佳选项。
One day, a boy found the cocoon(茧) of a butterfly and brought it home. A few days later, the boy saw a small 1 in the cocoon. He sat and watched for several hours as a butterfly struggled to make 2 body through that little hole. Suddenly it stopped.
So the boy 3 to help the butterfly, thinking the butterfly might be 4. He took a pair of scissors(剪刀) and cut the hole 5. The butterfly came out of the cocoon, but it 6 a little different. It had a weak body and small, thin 7. The butterfly didn't start to fly. In fact, the butterfly spent the rest of its life crawling(爬行) around with a weak body and thin wings. It was never able to fly.
The boy acted with 8 but he didn't understand why it could be like this. When a butterfly crawls out of the cocoon, it must struggle. The hard work of 9 out of the cocoon makes the fluid(液体) from the butterfly's body into its wings. It helps the butterfly be 10 to fly. If the butterfly never has to squeeze(挤压) itself out of the cocoon, its wings will never get the fluid and it can never fly.
11 struggles are what we need in our lives. If we lived our lives without any problems, we would never learn or grow. We would not be 12 we could have been and we would never fly.
In our lives, pain and suffering is the key to all windows, and sometimes even 13 growth, without it, there's no way of life. We can't avoid 14 or problems. So, next time you are 15 a problem or difficulty, remember the butterfly. Struggle a little–then fly!
