实际流体总流的伯努利方程的使用条件是（）.

A.稳定流、不可压缩流体

B.作用于流体上的质量力只受重力

C.运动沿稳定流动的流线或流速

D.以上三条

We haven’t discussed ______ yet.

A．where we are going to put our new table

B．where are we going to put our new table

C．what we are going to put our new table

D．what are we going to put our new table