题目

.There was so much noise in the room that the speaker couldn't make himselfA. being heardB. hearing               C. heard        D. hear 答案：C下列说法中正确的是（　　） A、HNO3的摩尔质量为63gB、标况时22.4升氧气约为1molC、一个氮原子的实际质量约为1gD、64g SO2中含有1mol O