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      11.13 since的四種用法
      ?
        1) since +過去一個(gè)時(shí)間點(diǎn) (如具體的年、月、日期、鐘點(diǎn)、1980, last month, half past six)。
        I have been here since 1989.
       
        2) since +一段時(shí)間+ ago
        I have been here since five months ago.


        3) since +從句 
        Great changes have taken place since you left.
        Considerable time has elapsed since we have been here.


        4) It is +一段時(shí)間+ since從句
        It is two years since I became a postgraduate student.













       學(xué)習(xí)啦--英語語法大全