1)
逗号的使用方法比较复杂,一两句不是能说清楚,最好比对 句号和分号的用法来看.
简单来说,一,逗号后面可以是一句话,he came here and had a look----he came here ,and he had a look.逗号成分要齐全.当然与此类似的还有but or yet 等等
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二后面接非限定定语从句 I learnt English well in the past,which helped me a lot when I worked
三逗号后接分词从句.The two boys were on their way to school,singing a funny song.
四表并列,相当于我们的顿号
五插入语,He ,a student from high shool,finally won the contest.
4 及物动词不加宾语 为省略,多用于口语
自己总结的,仅供参考