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问题 选择题

下面因式分解正确的是（　　）

A．a2-4a+4=（a+2）2

B．x2-y2=（x-y）2

C．x3-x=x（x2-1）

D．4x2-12xy+9y2=（2x-3y）2

答案

A、应为a2-4a+4=（a-2）2，故本选项错误；

B、应为x2-y2=（x-y）（x+y），故本选项错误；

C、应为x3-x=x（x-1）（x+1），故本选项错误；

D、4x2-12xy+9y2=（2x-3y）2，是完全平方公式，正确；

故选D．

单项选择题

The nurse is planning care for a client after a tracheostomy. One of the client’s goals is to overcome verbal communication impairment. Which of the following interventions should the nurse include in the care plan

A. Make an effort to read the client’s lips to foster communication.
B. Encourage the client’s communication attempts by allowing him time to select or write words.
C. Answer questions for the client to reduce his frustration.
D. Avoid using a tracheostomy plug because it blocks the airway.
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单项选择题

采用CIF贸易术语成交，其运输方式适合( )。

A．海上运输(包括内河运输)

B．陆上运输

C．各种运输

D．航空运输
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