1.in the tree指不是树上生长的叶子,花.指是树上生长的叶子,花时用 on the tree. 2.在世纪前用in ,in the 21st century 3.在年,月,星期,上午,下午,晚上前用in,in 2008,in May,in a week,in the morning ,in the afternoon,in the evening 4.在某一天前用on ,on Monday,on May 1st 5.在点钟前用at,at 8:00
1)in , on,at 在……时 in表示较长时间,如世纪、朝代、时代、年、季节、月及一般(非特指)的早、中、晚等。 如 in the 20th century, in the 1950s, in 1989, in summer, in January, in the morning, in the night, in one’s life , in one’s thirties...