"超声波在机体中传播时,由于对机体的机械作用,组织之间相互摩擦产热"属于()。
A.机械作用
B.温热作用
C.空化作用
D.局部作用
E.节段或全身作用
参考答案:B
The teacher commanded that the exercises _______ in an hour.
A. was finished B . were finished C should finish D. be finished
自喷油层等井口压力稳定后即可求产。