1.on ①在------上面 The book is on the desk. ②在------(哪一天/星期)What do you do on Wednesday? ③在------(月、日)My birthday is on August 2nd. 2.in ①在------里面 The pens are in the pencil-box. ②在------(哪一年/月)His birthday is in October. He wor ked here in 1992. ③在----(地方) He works in Dongguan. ④在----之内 What are you going to do in 20 years? ⑤在----(早上、下午、晚上) I do morning exercises in the morning every day. I usually play basketball in the afternoon. I often do my homework in the evening.