题目

下列说法中正确的是                                     （     ） A．H2SO4 的摩尔质量是 98 g            B．1 mol H2O 的质量是 18 g/mol C．Cl-的摩尔质量是 35.5 g/mol           D．1 mol N2 的体积是 22.4 L 答案：C1. As teenagers grow, it is normal for them to become ________ (困惑的)with the changing world both inside and outside of them.2 To remember so many words in such a short time is really ________ (挑战性) for an ordinary students. 3. She has been c________ with his friends online all the morning. No wonder she hasn’t finished the task yet. 4. If you eat the right food and exercise r________, you can feel better, look better and have more energy.5. After a heated a___________, a decision was finally made.