某气体的质量是9.5g，体积是5.6升（标准状况下），该气体的摩尔质量是（ ）
A．38
B．38g•mol-1
C．19
D．19g•mol-1
答案：B
---Did you go somewhere on holiday?
---I ____________ to go to Hawaii, but I didn’t sign up for the tour in time.
A．would hope
B．was hoped
C．had hoped
D．have hoped
过滤器压差大于（）时应进行冲洗。
A、0.01MP
B、0.05MP
C、0.10MP
