下列制冷剂中液态比水轻的是（）。 A.R12 B.R22 C.R134a D.R71_爱下问搜题

搜题请搜索小程序“爱下问搜题”

问题单项选择题

下列制冷剂中液态比水轻的是（）。

A.R12

B.R22

C.R134a

D.R717

答案

参考答案：D

多项选择题

咳嗽是指下列哪几项内容而言

A．肺失宣降

B．如水鸡声

C．肺气上逆作声

D．咯吐痰液

E．喉中痰鸣

补全对话，情景问答

选出正确答语填在横线上。

A. How much is it, please?
B. Oh yes. We have blue, yellow and white ones.
C. Which one would you like, please?
D. I'll take this one.
E. Can I help you?

A: 1.
B: Yes, please. I want to buy a sweater.
A: 2.             How do you feel this one?
B: I don't like black. Do you have other (其它的) colours?
A: Other colors? 3.
B: Can I have a look at the yellow one?
A: Yes, please.
B: 4.
A: Ninety yuan.
B: OK, 5.             Here is the money (钱).
A: Thank you.