我国进入社会主义现代化建设新时期的标志是[ ]

A．党的十一届三中全会

B．党的十五次代表大会  

C．新中国的成立

D．社会主义制度建立

He was chosen chairman of the Trade Union and he was happy to ________ the role.[ ]

A. take off  

B. take up

C. take over

D. take in