题目

____ the problem of method is solved, talking about the task is useless. A. Until                          B. Since                         C. After                    D. Unless 答案：B14．如图所示的化学实验基本操作正确的是（　　）A．点燃酒精灯B．读取液体体积C．闻药品的气味D．称量氯化钠