The building which now will be our science laboratory.A. is being builtB. will be builtC.

问题补充：

The building which now will be our science laboratory.

A. is being built

B. will be built

C. is built

D. has been built

答案：

(答案→)A. is being built

B. will be built

C. is built

D. has been built

解析：考查时态。根据语境可知建筑物正在被建筑，故用现在进行时的被动语态，选A。