_____ makes a new invention such a wonderful thing is ____ it allows us to do something ____ we could not do before.

A．What; what; what

B．That; that; \

C．What; that; \

D．That; what; that

ZD6电转机齿条块顶楔与移位接触触头间隙为（）mm。

A.1.0

B.1.5

C.2.0

D.2.5