there are always some traffic accidents happening easily when the road is ......为什么用happening?

分类: 作业答案 • 2021-12-20 02:27:13

问题描述：

there are always some traffic accidents happening easily when the road is ......
为什么用happening?

答

there be 句型+动词ing形式；be 是be动词,happen 是动词,不能同时存在两个动词,所以happen 采用现在分词形式