意：to continue to be in the same state or condition
例：Mooncakes remains an essential part of mid-autumn festival.
Remain: （不及物动词）；或（系动词，连接主谓）此时，remain几乎可以与Be动词同义替换。但remain更强调状态的稳定性和延续性。
remain+（否定性的）形容词。如unclear，unchanged，unproven，unanswered.
例：the fate of the injured remains unclear.
例：If it were Mr Ma of Alibaba, its shares would fall. If it were Mr Ma of Tencent, they would remain unchanged. And if it were Mr Li of Baidu, they would rise.（关于BAT三位CEO掉水淹死后股价的变化笑话）
remain+名词（如：a secret, an enigma)
例：whether the actor killed himself or was murdered still remains a secret.
= it remains unknown whether the actor kill himself or was murdered.
作业：
答：
1）Mid-autumn day remains one of the most popular festival for Chinese people.
2) 场景：韩春雨论文的可靠性仍未被证实。
造句：The reliablity of Han chunyu’s paper remains unproven.
