阅读理解。
Dear Harry Potter,
Hi! I'm Kevin from India. I really feel lucky to write you a letter.
Though I live far away from your world, I think we are a little alike, You are a great wizard (奇才). You
have done lots of magical things to be amazed at. Although I don't do magic. I do believe in it. Well, I'm also
a wizard at school. And I can often get As, but I am not a bookworm. I like to play jokes in class, which
sometimes make my teachers angry. I also have many friends. They often get me into and out of trouble.
No matter what has happened, we still get close together.
Oh, I almost forget to tell you that our school is almost like yours, Hogwarts. It's a special one for
excellent students. We have modern classes and technology lessons. But when much is given, much is
expected, so I often stay up late just to finish my homework. It really makes me tired and bored.
Luckily, I can read your stories in my free time. I feel like I know you. You have a mind of your own.
You are young, but you know how to take responsibility(责任) for your decisions. Also you think with a
clear head even in danger. What a great boy you are! How I wish I could meet you soon!
May you have a nice time.
Yours,
Kevin
1. Kevin and Harry are a little alike because _______.
A. they almost have the same experience
B. their worlds are full of magic
C. their schools are close to each other
D. they both like the same subjects
2. In the passage, "a bookworm" means a person _______.
A. who likes keeping worms
B. who is loved by teachers at school
C. who is nervous of reading books
D. who enjoys nothing but reading
3. From the passage we know that Kevin _______.
A. is a slow boy in class
B. is fed up with much homework
C. doesn't believe in magic
D. likes to keep quiet in class
4. Kevin writes to Harry to tell him many things EXCEPT _______.
A. his friends
B. his school life
C. his trouble
D. his family
5. Which of the following is NOT the reason (原因) that Kevin likes Harry?
A. Harry can do magical things.
B. Harry keeps a clear head in danger.
C. Harry likes reading stories.
D. Harry takes responsibility for what he has decided.
的过程中，粒子做加速度为
的匀加速直线运动，在
的过程中，粒子做加速度为
的过程中，粒子做加速度为
- T的过程中，粒子做加速度越来越大的变减速运动，由于加速度具有对称性，所以T时刻速度刚好减为零，然后重复刚才的运动，所以C是做单一方向的直线运动；
过程中加速度为负值，所以粒子反向做加速度运来越小的变加速运动，所以D不是做单一方向的直线运动。故选AC。