检修母线时，应根据（）等实际情况确定地线数量。
A、线路的长短
B、有无感应电压
C、检修工作重要性
D、工作人员多少
参考答案：A, B
下列所示文物，最有可能是图所示原始居民使用过的是
根据句意填空，首字母已经给出。
1. When you want to post a letter,you need a s______.
2. You room is u______.You need to clear it up.
3. Edison was so c______that he invented a lot of things.
4. You have collected all different kind of dolls.We can say you have a big
c______
5. Many students have h______such as reading,painting and so on.
