remain + adjective
remain 作连系动词，后接形容词，表示持续处于某种状态。
The children remained silent during the whole lesson.
整节课上孩子们都保持安静。
留下；停留；剩下；剩余；有待；留待；留下；逗留；在他人或其他部分离开或消失后仍留下。；剩余；余下；不包括在内。
to continue to be in the same state or condition; to stay unchanged
留下；逗留；在他人或其他部分离开或消失后仍留下。
To stay after others or other parts have been removed or otherwise disappeared.
剩余；余下；不包括在内。
To be left after a number or quantity has been subtracted or cut off; to be left as not included or comprised.
保持；继续存在；维持不变；经久。
To continue unchanged in place, form, or condition, or undiminished in quantity; to abide; to stay; to endure; to last.
等待；交由；留给。
To await; to be left to.
继续处于某种状态。
To continue in a state of being.
一般现在时
She remains confident despite the difficulties.
尽管困难重重，她依然保持自信。
一般过去时
After the storm, only a few houses remained.
暴风雨过后，只剩几座房子。
现在完成时
The problem has remained unsolved for years.
这个问题多年来一直未解决。
remain 常作系动词，后接形容词或名词，表示‘保持’或‘仍然是’。
After the party, only a few guests remained to help clean up.
聚会结束后，只有少数客人留下帮忙打扫。
用法提示：表示“留下”，是不及物动词，后接地点或目的状语。
She remained calm even when the situation became chaotic.
即使情况变得混乱，她仍然保持冷静。
用法提示：表示“保持（状态）”，后接形容词补足语。
The cause of the accident remains unknown despite thorough investigation.
尽管进行了彻底调查，事故原因仍然未知。
用法提示：表示“仍然是”，后接形容词或名词短语。
remain 作连系动词，后接形容词，表示持续处于某种状态。
The children remained silent during the whole lesson.
整节课上孩子们都保持安静。
后接名词时表示继续保持某种身份或性质。
He remained a teacher for over thirty years.
他当了三十多年教师。
She remained in her room all afternoon.
她整个下午都待在房间里。
用于表示某事尚待处理或完成，常用 work、much 等作主语。
Much work remains to be done before the project is finished.
项目完成前还有许多工作要做。
stay 更常用于指物理位置保持不变，而 remain 更正式
continue 强调动作的持续，而 remain 强调状态不变
persist 语气更强，暗示面对阻碍仍不改变
grammar · medium
易错句子The students remained silence during the ceremony.
正确表达The students remained silent during the ceremony.
remain 在此是系动词，后面要接形容词表示主语持续的状态，不能接名词；汉语“保持沉默”是动宾结构，学习者容易把名词 silence 直接放在 remain 后面，应改为形容词 silent。
grammar · medium
易错句子There remains many problems to solve.
正确表达There remain many problems to solve.
there be/remain 句型中，谓语动词要与后面的真正主语保持一致；此处真正主语是复数 many problems，所以要用 remain，而不能用第三人称单数形式 remains。
grammar · medium
易错句子Several questions remain to solve.
正确表达Several questions remain to be solved.
remain 后接不定式时，如果主语是动作的承受者，就必须用被动不定式 to be solved；用主动的 to solve 会让人误以为主语是执行动作的人。
stay 常指主动留在某地或不离开，也可指暂住；remain 更正式，强调别人离开后仍留下，或事物被去掉后仍剩下。表示“保持某状态”时两者都可能成立，但 remain 更书面。
keep 表示“保持”时多作及物动词或后接形容词，常含人为维持、使某物持续之意；remain 作不及物动词，直接接形容词或名词，强调状态持续，且更正式。
continue 强调动作或过程接着进行，常接 to do 或 doing；remain 强调仍处于某状态或仍存在，不强调动作本身的延续。
保持冷静
Try to remain calm during the emergency.
在紧急情况下尽量保持冷静。
保持沉默
He chose to remain silent about the incident.
他选择对这件事保持沉默。
保持不变
The rules remain unchanged for this year.
今年规则保持不变。
留在原地
Please remain in place until further notice.
请留在原地，直到另行通知。
留下；逗留
Some students remained behind after class to ask questions.
一些学生课后留下问问题。
常与remain搭配，表示状态未变
强调持续不变的状态
表示动作或状态继续
指事物被留下或未被使用
强调继续存在或发生
有待观察
Whether the new policy will be effective remains to be seen.
新政策是否有效还有待观察。
蒙在鼓里
The public remained in the dark about the company's financial troubles.
公众对公司的财务问题一直蒙在鼓里。
保持秘密
The details of the negotiation remain a secret.
谈判的细节仍是个秘密。
Dictionary facts from ECDICT, WIKTIONARY.
保持坐着
All passengers should remain seated until the plane has stopped.
所有乘客应保持坐着，直到飞机停稳。