I ______ in a foreign company in Shanghai for six years. Still, I don't regret giving up the well-paid job and returning to my hometown.[ ]

A. worked        

B. have worked      

C. was working    

D. had worked

对限速器安全钳联动试验时，分别以（）往下运行，并且在运行过程中，手动托起限速器抛球，让限速器抛块夹住限速器钢丝绳，安全钳应动作。

A.检修速度和平层速度

B.额定速度和检修速度

C.平层速度和额定速度

D.额定速度