联合接地就是将（）、（）和（）共同合用一组接地体的方式。
参考答案：工作地；保护地；防雷地
动词填空。
1．My best friend Kitty _____(study) in Shanghai.
2. _____your fridends usually_____(fly) kites in the park ?
3. After school, he always ____ (finish) his homework first.
4. Would your brother like _____(teach) me how to make model planes?
5. We should _____(practise)speaking English every day.
如何预防泌尿系结石?
