若集合A1,A2满足A1∪A2＝A,则称(A1,A2)为集合A的一种分析,并规定

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问题选择题

若集合A₁,A₂满足A₁∪A₂＝A,则称(A₁,A₂)为集合A的一种分析,并规定:当且仅当A₁＝A₂时,(A₁,A₂)与(A₂,A₁)为集合A的同一种分析,则集合A＝{a₁,a₂,a₃}的不同分析种数是（）

A．4

B．8

C．27

D．15

答案

答案：C

填空题

用所给单词的适当形式填空。

1. My parents allow me____ (choose) my own clothes.

2. Young people need (sleep) about 8 hours at least every day.

3. He has to (take) a TOEFL exam if he wants to go to an American school for

further study.

4.－I have three English magazines.

－I have nine. I have three times as (more) as you.

5. What kind of clothes would he like (wear)？

多项选择题

动臂式起重机的性能及主要参数有（）。

A.工作幅度

B.起重力矩

C.支腿跨距

D.工作速度

E.工作跨度