there are many foreigners visiting the Great Wall every year句中的visit为什么要加ing
问题描述：
there are many foreigners visiting the Great Wall every year句中的visit为什么要加ing
答
这个是句型,there be +名词+doing的结构再问个题she had turned off the light,had做什么用这个是过去完成时，那个是过去完成时的标志