it is high time that有的在后面加（should）+动词原形,有的在后面加虚拟语气如It is high time that suc

就两种用法.
It is (high) time that后面的从句谓语动词
要么用过去式或者用should+动词原形,但should不可省略.
如：
It is high time that the children went to school.
It is high time that the children should go to school.lYU影风网