—Jack called to say that he would not accept the job .

—I had talked him into taking it up many times .      since he still refuses .

A．I’ll come to his help

B．I can’t help it

C．I’ll talk it over with him

D．I’ll phone him up

在物理学研究中，有时可以把物体看成质点，以下说法正确的是（ ）

A．研究乒乓球的旋转，可以把乒乓球看成质点

B．研究奥运冠军郭晶晶的优美跳水动作时，可把郭晶晶视为质点

C．研究神舟七号飞船绕地球运动的周期时，飞船可视为质点

D．研究车轮的转动，可以把车轮看成质点