疑问句中出现这几个情态动词时，yes或者no后面情态动词要干什么变化吗？
Dare you try again? No,I dare not. Yes,I dare..
Shall we do that immediately? No ,we shall not. Yes,we shall.（可以如此回答吗？shall用作情态动词时可以用于第一人称的一定句吗？）
Should he do homework now? No, he shouldnt. Yes, he should.
Would you please open the door? Yes ,I will. NO, I wont.
5. No mistakes can be made during paper cutting,or the work would fail.(这里would不是用于表示过去，更不是表示推断，请问为何用过去式呢？）
谢谢各位老师的解答。
学习英语要灵活，不可以死板。了解一般疑问句的一般回答规律是一回事，具体语境中怎么样回答是另一回事。就好比汉语，你吃了吗？吃了/没吃呢。但：你贵姓？就不可以回答：我贵姓王。而是：免贵姓王。
英语也是这样，当问话人用非常礼貌的形式问你时，情态动词表示对你的尊重，你回答时就要避开这个情态动词。以下是实质交际中，可能的答句：
Dare you try again? Why not? / No, I wont do it again.
Shall we do that immediately? Yes, we/you must. / No, we/you dont have to./we/you neednt.
Would you please open the door? Ok/No problem. / Sorry, I cant.
No mistakes can be made during paper cutting, or the work would fail.
这就是所谓的“含蓄虚拟条件句”的状况之一。or=otherwise. 暗含了一个if 从句：If any mistake were made during paper cutting, the work would fail.
