— Mrs Green is angry with Mary. It seems ______ she is going to call her mother. 

— Right, let’s persuade Mary to give up now.

A as if                      B as long as

C even if                   D in order that

螺杆泵（）、无噪音、流量均匀。适用于输送粘稠液体。

A、扬程高

B、扬程低

C、效率高

D、效率低