【—since的】since的后面一般可以加一段時間、一個時間點或者是一個從句的四種用法。

　　1) since +過去一個時間點　(如具體的年、月、日期、鐘點、1980, last month, half past six)。

　　I have been here since 1989.

　　2) since +一段時間+ 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 +一段時間+ since從句

　　It is two years since I became a postgraduate student.

　　關(guān)于since的四種用法是我們在英語中幾乎是隨處可見的，所以同學們不可以馬虎了。

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