王乙与曹某签订的售房协议是否有效为什么

C注册会计师是K公司2009年度财务报表审计的项目负责人，在对相关账户抽样时，有一些涉及审计抽样及抽样风险的问题，请代为作出专业判断。

在编制审计计划时，需考虑影响样本量大小的有关事项，对审计抽样工作进行规划。以下各项表述中，正确的是( )。

A．可接受的抽样风险越低，需选取的样本量越小

B．总体项目的变异性越低，需要的样本规模越大

C．可容忍误差越小，需选取的样本量越大

D．预期总体误差越小，需选取的样本量越大

阅读理解。

    Welcome to the zoo, everyone! Here is our plan. Listen carefully. First we will visit

the Children's Zoo. After that, we will walk to the Bird World. Next is the African (非

洲) Area. There are elephants and lions! Don't be afraid. The cages (笼子) are safe.

    Then, we will have lunch. Maybe some of you don't have drinks. That's all right.

There are many places to buy drinks.

    After lunch, we will go to the Asian (亚洲) Area. Last, there is the Butterfly Park.

Then, we will come back here and get on the bus. Remember, don't feed the animals.

OK, let's have some fun!

1. The Butterfly Park _____. [ ]

A. is the first place to visit

B. is the last place to visit

C. is in the Children's Zoo

D. is a part of the Asian Area

2. What is near the Bird World? [ ]

A. Children's Park.

B. Butterfly Park.

C. African Area.

D. Asian Area.

3. Which of these is first? [ ]

A. Visiting the Asian Area.

B. Eating lunch.

C. Seeing the African Area.

D. Going to the Bird World.

4. Students without drinks _____. [ ]

A. can buy a drink at the zoo.

B. cannot do anything

C. can only go into the Children's zoo

D. will get drinks from the teacher

5. People at the zoo should not _____. [ ]

A. visit the Butterfly Park

B. look at the lions

C. give food to the animals

D. Bring their lunch

影响稳定爆轰的主要因素是：（）、（）、（）。

作液压支架前应注意那些问题？