given的用法（give）_______more instruction,thestudents would have

given的用法
（give）_______more instruction,thestudents would have done the exercisemuch better.是填Given,还是Had been given?为什么
详细告诉我为什么不能用Had been given的我再给分，按我的理解对过去的虚拟从句应该用过去完成时，而选given,还原的话是if they were given more instruction,这个是过去式，不符合一般虚拟语气的表达方式。你一定觉得填Given对的话，那我再反问一句，在这样的情况下，横线上填什么？（give）_______more instruction,the students would do the exercise much better.