阅读理解。
July 5, 2007
Dear Tony,
Thank you for your letter. I read it today after school, and now I want to tell you all about my hobbies. I like to swim. In summer, l swim every day.
I also like reading. I read all kinds of books. I often read two or three books a week. I enjoy writing
stories, too. I want to be a writer in the future (将来).
I also like to play with my dog. His name is Mickey. On weekends, we like to go for long walks.
Mickey is a big dog, and needs a lot of exercise. There is a lake near my house. We often walk around the lake. Mickey likes to jump into the water. He's a good swimmer. It is a beautiful place. There are many
flowers. Mickey and I like to look at the flowers.
Well, these are my hobbies. Do you like to read? Do you have a dog? Please write and tell me
about your hobbies.
Your friend,
Karen
1. What is this letter about?
A. It is about a lake.
B. It is about Karen's hobbies.
C. It is about Karen's family.
D. It is about swimming.
2. What does Karen do every day in summer?
A. She swims.
B. She reads.
C. She writes.
D. She goes for long walks.
3. How many books does Karen read a week?
A. Only one book.
B. No books.
C. Two or three books.
D. Many kinds of books.
4. Who is Mickey?
A. Karen's dog.
B. Karen's brother.
C. The lake.
D. Karen's friend.
5. Where do Karen and Mickey go for long walks?
A. In her house.
B. In the park.
C. Around the lake.
D. In the neighborhood.
，则运动员在这两坡段运动平均速度之比及加速度之比各为多少？
，
，得：v1=2v2
， 
得：a1:a2 = 2:3
=" 7300" N