都是被动语态,时态分别为：
shall be asked .将来时
should be asked .情态动词should 现在时
would be asked .过去将来时（或者虚拟语气现在时）
would have been asked 虚拟语气的过去时would have been asked 也是过去将来完成时吧？should be asked也是过去将来时？1. 过去完成时的表达是：had been asked2. should 是情态动词“应该”的现在时，本身这个词没有过去时，如果要表示后悔“本来应该做某事”，可以用它的完成时态：should have dong sth.