活泼的醛、酮和有机酸与卡尔·费休试剂中的甲醇发生()释出水。
A.加成反应,酯化反应
B.酯化反应,加成反应
C.酯化反应,羟醛缩合反应
D.羟醛缩合反应,酯化反应
参考答案:D
单词拼写。根据句意和首字母或汉语提示,将单词的正确形式写在题中相应的横线上。
1. O_________ cover more than 70 percent of the earth's surface.
2. Could you please speak more s__________, Tom? I can't catch what you say.
3. __________ (数以百万计的) of people around the world cannot get clean water.
4. A scientist says that beautiful music can make cows __________ (生产) more milk.
5. Paris has some fantastic sights, __________ (包括) the Eiffel Tower and Notre Cathedral.
烈性噬菌体