— Don't you think it necessary that he _____ to Miami but to New York?

— I agree, but the problem is ______ he has refused to. [ ]

A. will not be sent; that

B. not be sent; that

C. should not be sent; what

D. should not send; what

管路中出现管子振动的情况该如何处理。（）

A、换一个更为结实和牢固的管子

B、用管支撑固定或撤掉管的支撑件

C、用支管固定

D、撤掉支管