－Miss Jones once _________ music at a local college for ten years and now is an actress.

－No wonder I often hear her sing some pop songs.

A．had taught

B．has been teaching

C．taught

D．is teaching

船舶作舵旋回进入定常旋回阶段后，下列叙述哪项不正确？（）

A.作用于船体的合力矩为零

B.角速度达最大

C.角加速度达最大

D.船舶降速达到最大