—What a nice classroom!

—It _____ every day. [ ]

A. is cleaning

B. has cleaned

C. must clean

D. is cleaned

关于硬膜外麻醉,以下哪项叙述是错误的

A．老年人比青年人麻药用量少

B．在孕妇，麻药可能转移到胎儿

C．麻醉药也可进入蛛网膜下腔

D．比腰麻引起的血压下降轻

E．硬脊膜囊终止于第五腰椎水平