once you have cured the water pollution,you will have to take steps to avoid it___again.这里填happens,而不是to happen,happenin
问题描述：
once you have cured the water pollution,you will have to take steps to avoid it___again.这里填happens,而不是to happen,happening对吗?
答
avoid是及物动词,后面可以直接接名词,代词,动名词或者是接that从句.没有avoid sb.to do/doing结构.在这个题中是接的省略引导词that的从句.
刚刚看到楼上说可以接happening,是不对的,如果要接的话,it要改为物主代词its才对.