楼板支架的计算中，能够计算楼板强度的是（）计算模块.

阅读理解。

     Many teenagers feel that the most important people in their lives are their friends. They believe that their

families don't know them as well as their friends do. In large families, it is quite often for brothers and sisters

to fight each other and then they can only go to their friends for some ideas. It is very important for teenagers

to have one good friend or a group of friends.

     Even when they are not with their friends, they usually spend a lot to time talking among themselves on the

phone. This communication is very important in children's growing up, because friends can discuss something. There things are difficult to their family members.

     However, parents often try to choose their children's friends for them. Some parents may even stop their

children form meeting their good friends. Have you ever thought of the following questions?

     Who choose your friends? Do you choose your friends or your friends choose you? Have you got a good

friend your parents don't like? Your answers are welcome.

1. Many teenagers think that their _____ can understand them better.

A. sisters

B. brothers

C. friends

D. parents

2. _____ is very important to teenagers.

A. Making friends

B. Meeting friends

C. Living with friends

D. Fighting with friends

3. Teenagers usually like to ______.

A. go to their brothers and sisters for help

B. communicate with their parents

C. make friends with their parents

D. discuss something with their friends

4. The sentence "Your answers are welcome" means "_____"

A. Your answer are right

B. You should give us all the right answers

C. We'd like to have your ideas about the questions

D. You are welcome to understand your friends.

5. According to the writer, parents should _____.

A. choose for their children

B. understand their children better

C. welcome all their children's friends

D. stop their children from choosing friends.

血气分析仪在测量样品前确定电极的工作曲线的是下述的（）

A.标准缓冲溶液

B.标准液

C.标准气体

D.标准液和标准气体

E.冲洗液

零缺陷管理法以零缺陷为管理目标，其最优的结果是（）。

A.零缺陷

B.低缺陷

C.免事后处理

D.低处理费用

E.零管理费用

你的总工程师估计一个工作包大约需要50周来完成。如果一切顺利将在40周内完成，但在最坏的情况下需要180周完成。利用PERT估计完成该工作包的期望时间是（）

A.45周

B.70周

C.90周

D.140周

简述毒理学的两大功能。