Although he          in America for a long time, he’s never regretted his making his mind to return to his own country.

A．stayed

B．was staying

C．has stayed

D．had stayed

（）之日起泥浆工开始坐岗。

A、从安装防喷器开钻

B、从开始录井

C、开钻

D、钻开油气层