We still have some minutes left before the end of the exam. There _____ answering chances for us. [ ]

A. should be

B. must be

C. shall be

D. might be

对于高大空间的建筑物，仅要求下部区域保持一定的温湿度时，宜采用（）气流组织方式.

A、分层式送风

B、下部送风

C、侧送风

D、顶部送风