Though some foreign scientists had a ______ opinion of his new invention, his fellow workers never thought ____ of it.

A．highly; low 　

B．low; high

C．high; highly

D．poor; highly

全泵投入以后的设计理论真空度是（）。

A.67pa

B.8.7kpa

C.2.5kpa

D.0.5kpa