人教新课标高中(必修3) Unit4 同步练习[下学期] 【编号:4-52448】
元知识点分类练习
一、根据中文或首字母提示,填写所缺单词的适当形式。
1. There is a friendly a________ of helping each other with difficulties in study in our class.
2. It is possible to ________ (繁殖) these bacteria in the laboratory.
3. By the time they reached the top of the mountain they were e________.
4. There is a big underground railway ________ (系统) in London, whi