The village in _______ I once worked has changed a lot. [ ]
A. which
B. /
C. that
答案:A
有一种气体的质量是14.2g,体积是4.48升(标况下),该气体的摩尔质量为( )
A.28.4
B.28.4g·mol-1
C.71
D.71g·mol-1
在机组甩全负荷情况下,要求调节系统能够维持机组转速在()之下。