单项选择题
A.water
B.oil
C.scale
D.ridge
单项选择题 The diameter of the crank-pins should be measured with a ().
单项选择题 The development of () has kept pace with the increasing demands made by the steady rise in power produced by modem marine diesels.
单项选择题 The design of the connecting rod large end bearing is similar to that of the mainbearings Whats the meaning of "that" in the sentence above?()