清代散文大派（）的三个代表人物是：方苞、姚鼐、和刘大魁。
查看答案
我国城市燃气管道按输气压力来分，中压B燃气管道压力为（）。
A. 0.01MPa≤P≤0.2MPa
B. 0.2MPa＜P≤0.4MPa
C. 0.4MPa＜P≤0.8MPa
D. 0.8MPa＜P≤1.6MPa
采光口在为室内提供天然光照度的同时，一般情况下也兼做通风口，同时又是保温隔热的薄弱环节，对于有爆炸危险的房间还可做为（）。
Control valves of a CO2 system may be located within the protected space when（）.
A. it is impractical to locate them outside
B. there is also a control valve outside
C. the CO2 cylinders are also in the space
D. an automatic heat-sensing trip is installed
微信支付 
支付宝支付