题目

下列实验操作正确的是 （     ）                                          A. 吹灭酒精灯     B. 闻气体气味         C. 量取液体        D. 滴加液体 答案：D________ global financial crisis is ________ challenge for the whole world. Confidence, cooperation and responsibility are the key factors to overcome the crisis. A. A; the　　 　B. A; a　　 　　C. The; the　　　D. The; a