税务师事务所应当周期性地对已完成的业务进行检查，周期最长不得超过( )年。A．1 B

比一比．

84982八八______k65432八八

k35万______k35八八八八

6八八2k八八八______6八八k2八八八

48八×6______6八×48

86×2八______8八×26

398×2______3k×98．

供配电系统的逆调压是指（）。

A、负荷增加，送端电压往高调，负荷减少，送端电压往低调

B、负荷增加，送端电压往低调，负荷减少，送端电压往高调

C、无论负荷增加或减少，送端电压往高调

D、无论负荷增加或减少，送端电压往低调

A: I’m not sure what Dr. Tyler wants us to do.
B:().

A. So you didn’t come to the class yesterday

B. I’ll make a call to him if you don’t mind.

C. Oh, you’d better guess it out by yourself.

D. If I were you, I’d write and ask Dr. Tyler to look at it.

简述XY一4型钻机液压操纵阀的基本结构。