Many old buildings _____ in order to build the EXPO garden. [ ]

A. were put down

B. pulled down

C. were pulled down

D. put down

对ZDl05型牵引电动机进行耐压试验，电枢通4000V电压（）应无闪烙、击穿。

A、lmin

B、2min

C、3min

D、4min