题目内容：

Are you free__tomorrow night? A.on B.in C.at D.不填

优质解答

选D
在表时间里,下列情况下一般不用介词.词组里有：next,last,this,that,tomorrow,yesterday,one,every,all以及the day before yesterday和the day after tomorrow前不用介词.如：不能说in tomorrow ,只能说tomorrow(在明天)