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帮我看一下这个英语句子

来源:学生作业帮 编辑:拍题作业网作业帮 分类:英语作业 时间:2024/04/28 13:26:13
帮我看一下这个英语句子
Fog and haze is an serious problem needed to solve.我想知道那个needed用的对不对
或者Fog and haze is an serious problem which need to solve呢?to用不用加?
Fog and haze is an serious problem needing to be solved.
Fog and haze is an serious problem which/that needed to be solved.