過去將來時的搆成是什麽？

過去將來時的基本特征，也就是我麽年今天所談到的“立足過去，著眼未來”。它表示從過去某一時間來看將要發生的某個動作或存在的某種狀態。例如：Mary told me that she would go to Shanghai by plane.那麽過去將來時態的搆成是什麽呢？它都有哪些用法呢？

基本搆成——

A ) would + 動詞原形

如He asked me if I would stay here. 他問我是否要待在這兒。

B ) was / were going to + 動詞原形

如No one knew when he was going to finish his homework.

C ) was/ were ( about ) to + 動詞原形

如：He said that they were to leave at six.

She said that the meeting was about to begin.