制冷压缩机的主要作用是对制冷剂蒸气进行（）。A、吸气 B、排气_爱下问搜题

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问题单项选择题

制冷压缩机的主要作用是对制冷剂蒸气进行（）。

A、吸气

B、排气

C、压缩

D、做功

答案

参考答案：D

名词解释

草地杂草

补全对话，情景问答

选用方框内的句子完成对话。

a. You may ask that policeman.
b. The middle school is on your left.
c. Would you please tell me the way to the No. 3 Middle School?
d. Is that a long walk?
e. Thank you very much.

A: Excuse me.
B: Yes?
A: 1____________
B: Sorry. I don't know. 2____________
A: Excuse me, sir?
C: Yes?
A: How can I get to No. 3 Middle School?
C: Go along this street, and then turn right. 3____________
A: 4____________
C: No, it's about 100 metres away.
A: 5____________
C: That's all right.