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
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
参考答案:D
选用方框内的句子完成对话。 | |
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. |