I don’t believe these people have achieved success __________. They must have put much effort into their work.

A．by coincidence

B．as usual

C．in particular

D．on purpose

测量管的作用是（）

Ⅰ．测量所有的压载水舱；

Ⅱ．测量所有的淡水舱；

Ⅲ．测量所有的燃油舱；

Ⅳ．测量污水沟或污水井。

A.Ⅰ，Ⅱ，Ⅲ

B.Ⅱ，Ⅲ，Ⅳ

C.Ⅰ，Ⅲ，Ⅳ

D.Ⅰ，Ⅱ，Ⅲ，Ⅳ