Don't go to bed late __school nights.A.at B.on C.in D.by

问题描述:

Don't go to bed late __school nights.A.at B.on C.in D.by

B因为nights前有school修饰,使它变成一个特定的时间而不是泛泛而谈,所以要加on ,at只有at nights,in就不加nights只有in the evening ,by大多数是用在完成时中,而后面加时间时不常用在现在时中eg:By the end of last night,I had finished my homework .