--- The dish looked bad, but it_______ OK.

--- So it's not right to judge a man by his appearance.

A． tastes

B．was tasting

C．was tasted

D．tasted

利用一种流体在运动过程中的能量变化来输送另一种流体的泵称为（）。

A.喷射泵

B.螺杆泵

C.混流泵

D.齿轮泵