关于力点叙述正确的是（） A.在骨杠杆上是肌肉的附着点 B.是杠杆绕着转动的轴心点

阅读理解。

     Have you ever had problems in your life and don't know how to be happy? If so, you will find Being a Happy Teenager written by an Australian writer Andrew Matthews.

In his book, Matthews tells us how to have a happy life and answers the questions of teenagers.

     There are many subjects, such as parents and friends, and the book says we should stop being angry

and should forgive(宽恕). The book tells us some useful skills, such as how to put what you have learned

into pictures of your mind to, make your memory better. Many teenagers think that happiness comes from a good exam result or 'praise(费扬) from other people. But you can still be happy when there are no such "good" things.

     Success comes from a good attitude(态度). If you learn from problems, you will have success in the

future. Some school students have problems, such as being too tall or too short. But Matthews tells us that happiness comes from thinking in a positive(积极的) way. If you are tall, people notice you and you can

get a better view(视线) at the movie; if. you are short, your clothes and shoes take less room in your

bedroom! This is Matthews' most important lesson: 6*You choose to be happy! "

根据短文内容，回答下列问题 。

1. What's the name of the book written by Andrew Matthews?

2. What's in Matthews' book?

3. According to the passage, where does happiness come from to many teenagers?

4. Is it right to think in a positive way?

5. What's Matthews' most important lesson?

简述在以私有制为基础的商品经济中价值规律的作用。

会议能否顺利举行，关键在于是否做好了会议前的（）。

半抗原可刺激动物产生抗体的条件是（）

A.免疫动物皮下注射

B.免疫动物静脉内注射

C.采用特定动物进行免疫

D.应用佐剂配合

E.和载体结合

新生儿每日睡眠时间可达（）小时。

A、10-12

B、12-16

C、16-20

D、18-20