单项选择题
What color is used to indicate the last shot of anchor chain?（）
A.Red B.White C.Blue D.Yellow
单项选择题 A vacuum is initially created in a flash type distilling plant by（）.
单项选择题 A refrigeration unit will tend to short cycle when operating （）.
单项选择题 Which of the following problems could cause air to blow out through the inlet air filter of a running compressor?（）
