Thomas Alva Edison didn’t “invent” the light bulb (灯泡), but rather he ______ a 50 –year –old idea, which is not well –known.

A．improved upon

B．take down

C．put up

D．break away

某综合办公楼设置了水喷雾灭火系统进行防护，该系统水雾喷头的工作压力不应小于（）MPa。

A.0.05

B.0.1

C.0.2

D.0.35