R134a
参考答案:
R134a是指一种新型无氟环保制冷剂
Eating too much fat can ________ health problems,so we must have a balanced diet.
A.lead to
B.result from
C.refer to
D.devote to
防止座舱外部气压大于座舱内部气压的是().
A.正压释压活门
B.安全活门
C.负压活门
D.压力均衡活门