in /on/ at 表示空间方位
图示
in：
①在......内部 in the box
②在大地方（country, city, district, neighborhood）
in England, in Shanghai, in Jing’an district, in Chinatown on：
①在......上面（接触）on the box
②在......街道/转角 on South Nanjing Road
③与......接壤 Jiangsu is on the north of Zhejiang. at：
①在......附近 at the door
②在小地方（门牌号，小地点等） at 111 South Nanjing Road, at the airport, at the store
in /on/ at 表示时间 in：
①年份 in 1998
②季节 in summer, in the summer of 1998 ③月份 in September
④早、中、晚 in the morning, in the afternoon, in the evening ⑤一段时间后 in a minute, in two weeks on：
①某一天 on January 1st
②星期中的一天 on Friday, on Sunday
③某些节日 on Christmas Day, on my birthday
④某一天的早、中、晚 on the morning of January 1st at：
①特定时段 at noon, at night ②时点 at 6 o’clock, at midnight
③节日庆祝期间 at Christmas, at Easter
对比：
in the morning on the morning of January 1st on Christmas Day at Christmas
in the north of…; on the north of…; to the north of…