1.保持教室干净是keeptheclassroomquiet还是keepquietintheclassroom.2.做晚饭是makedinner还是cookdinner3.night的介词是at,可为什么schoolnight（上学日的晚上）的介词是on?

Question

1.保持教室干净是keep the classroom quiet还是keep quiet in the classroom.
2.做晚饭是make dinner还是cook dinner
3.night的介词是at,可为什么school night（上学日的晚上）的介词是on?

Answer 1

1）用keep quiet in the classroom,而keep the classroom quiet使教室安静,教室自身怎么能安静?keep the classroom clean倒可以,所以一般不这样用.
2）两者都可以,你可以在百度上找到相应的例句.
3）night前面本来就既可以用on,又可以用at,区别是at night只能表达某一个晚上,而on night泛指夜晚（也就是复数）