题目

I had been a step-mother for six years, and with my husband，I had watched his young children growing into teenagers. Although they lived mostly with their mother, they spent a lot of time with us. Over the years, we all learned to become more comfortable with each other. However, I continued to feel somewhat like an outsider. When the children moved to a town five hours away, my husband was understandably destroyed. In order to keep in touch with the kids, we set up an e-mail and chat-line service.Ironically (具有讽刺意义的是), this technology can make us feel out of touch and more i17．下列说法正确的是（　　）A．单位体积溶液里所含的溶质的物质的量，叫做物质的量浓度B．气体摩尔体积就是22.4L mol-C．摩尔质量就是微粒的相对分子质量或者相对原子质量D．物质的量就是物质的质量