在白蚁群体内部不同成员之间分工合作，共同维持群体生活．这种行为属于（　　）

A．社会行为

B．取食行为

C．生殖行为

D．防御行为

Mr. Lee, who            as a carpenter for over 10 years, is now a very famous statesman in this country.

A．has worked

B．had worked

C．worked

D．works