When I was a little child ，my parents took me to German. 小题1: .When I came back, I could speak German fluently. “ Can I do something useful with German?” I asked myself.
Then, I got a good opportunity last spring. During that time our university had a long holiday, so I stayed at home with nothing to do. 小题2: . “ Why don’t you translate(翻译) it into Chinese? It will be better than playing computer games all day.” I agreed happily.
I promised to do 4,000 words each day. But soon I found it was hard to keep the promise.
One day in May, the weather was beautiful. 小题3: .Those 4,000 words were still waiting for me. After translating only three pages, I already lost interest in the book. I looked at it for a long time. But I couldn’t make myself turn the pages. 小题4:
I counted (数)the words again and again. I just wanted to give up. I felt as if two people were fighting in my mind. One said, “Don’t give up! Keep working hard ,and you will do well!” But then the other one said, “Go and play! It will be more interesting than translating. Do your homework tomorrow.”
I stood up and would turn off the computer. But then I remembered what my parents had told me, “ Whatever(无论什么) you do, don’t stop half way.” 小题5: .
A．My father brought me a German book
B．So I sat down and went on with it
C．But I couldn’t go out
D．I lived there for nine yearsE. How I wished I could just go outside and play basketball with my friends!
可见，动能与速度相关，返回舱质量不变，速度变小，动能变小，同时，高度下降，重力势能变小，势能变小，动能和势能都变小，故机械能变小。故答案选C.