emain 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.
remain:仍然是=still be, remain是不及物动词,只能说 sth remains,sth remained.It remains a mystery.
leave表示“剩余”的时候,在句中经常表现为
1. sb leaves sth to sb
2. sth was left
Nothing was left after the fire.
习惯用语：it remains to be seen 还要看情况发展
用法1、sb./sth. remain+ n./adj.意思是“...依然...”
2、sth. remain to be done意思是“...有待被做”
3、sb. remain doing sth.意思是“...依然在做...”