would have to 是will have to的过去式，表示后面跟随的动作将会可能发生，但是还没有发生。would have to用在过去式中，will have to 用在现在时和将来时中。have to 是不得不，必须这类含义。
she said we would have to stay here
she said we had to stay here
He would have to explain the situation to his officials and to the public and pace the changes so that people could accept them and the country would not split apart.
would have to 在虚拟句式中也可以见到，在虚拟条件列出的前提下，would have to表示在此前提下可能做的事情，可能发生的动作。这时的前提假设，针对的是当下，或者未来的时刻。
Should it rain tomorrow, we would have to stay home.
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