300mL某浓度的NaOH溶液中含有60g溶质,现欲配制1mol/LNaOH溶液,应取原溶液与蒸馏水的体积比约为 A. 1∶4 B. 1∶5 C. 2∶1 D. 2
---I’m going to Sanya for my holiday tomorrow. —_______A.Have a good time!B.You’re right.C.It’s good.D.Goodbye!
四、 阅读理解选出最佳选项 (共40分) I was waiting for a phone call from my agent. He had left a message the night before, telling me that my show was to be cancelled(取消). I called
将一植物放在密闭的玻璃罩内,置于室外进行培养。假定玻璃罩内植物的生理状态与自然环境中相同,用CO2测定仪测得了一天内该玻璃罩内CO2浓度变化
She says she will come to visit our school _____ next week. A. sometime B. some time C. some times D. sometimes
.类推的思维方法在化学学习与研究中有时会产生错误结论,因此类推的结论最终要经过实践的检验,才能决定其正确与否,下列几种类推结论中,错
定义在上的函数满足,则的值为 (A) (B) (C) (D)