it'll be cheap to travel everywhere by plane的形式主语和真正主语是、 并且希望是能够加上it····to···的用法、注意事项等等.

问题描述:

it'll be cheap to travel everywhere by plane的形式主语和真正主语是、 并且希望是能够加上it····to···的用法、注意事项等等.

形式主语是it,真正主语是to travel everywhere by plane
常用的句型是it is +adj.+to do sth