remain 是不及物动词也可以做系动词,意思是保持不变,近似于keep的含义.后接形容词、名词、介词短语等作表语eg.She remained silent through the discussion.
leave是及物动词,这时的“留下”指“剩余”.eg.在Several problems remain to be solved.中,remain意思相当于be left（leave的被动语态）.再如Leave me alone.