9、過去完成時
    John had learned some Chinese before he came to China. He found the book that he had lost.
    By the end of last year， I had worked in this college for ten years.
    no sooner………than， hardly(scarcely)……when(before)
    We had no sooner reached home than it began to rain. No sooner had we reached home than it began to rain.
    He had hardly entered the office when (before) the phone rang.
    10、現(xiàn)在完成進行時(常跟for hours， since this morning等表示一段時間的狀語連用)
    They have been watching TV for two hours. He has been working on this essay since this morning.
    11、時態(tài)呼應特殊規(guī)則
    Kepler proved that the sun is the center of the solar system. 客觀真理
    I didn‘t go to the ball because I am not fond of dancing. 意義需要
    被動語態(tài)
    一般時態(tài) 進行時態(tài) 完成時態(tài)
    現(xiàn)在 am
    is written
    are am
    is being given
    are has
    been written
    have
    過去 was
    were written was
    were being given had been written
    將來 shall
    will be written shall
    will have been written
    過去將來 should
    would be written should
    would have been written