on in at这三个介词后面跟时间时，有什么区别，用法上的

on+准确日期，比如2008.8.8，IN加年，比如1995，AT加点，比如八点半

1、时间介词
in,
on,
at
at
<
天
(eg.
noon,
dawn,
night,
one’
clock)
on
=
天
(Monday,
30th
June,
New
Year’s
Day,
Mother’s
Day)
in
>
天
(2008,
summer,
April,还有早午晚)
注意:
1)
早午晚前后如有修饰语则用
“on”
On
Monday
morning
On
a
sunny
afternoon
On
the
morning
of
May
23rd
On
a
dark
night
2)
on,
in,
at不用于下列时间之前:this,
that,
last,
next,
every,
each,
today,
yesterday,
tomorrow,
tonight
3)
in+一段时间可以表“…之后”
Eg:
Hurry!
The
school
bus
will
leave
in
five
minutes
I
will
see
my
grandparents
in
a
few
days.
2、方位介词:
1)at和in
in
大地点
≥town
at
小地点
<
town
eg.:
in
town
at
bus
station
in
Beijing
at
school
in
USA
2)on表示在物体表面上
eg:
on
the
table
,
on
the
wall
注意:1)
on
the
tree
长在树上
There
is
an
apple
on
the
tree.
in
the
tree
呆在树上
There
is
a
bird
in
the
tree.
2)on
the
wall
挂在墙上
There
is
a
picture
on
the
wall.
in
the
wall
嵌在强中
There
is
a
window
in
the
wall.

at 时间点，
有on必有天，
in加月季年，
也和晌相连，
上下这那每之前，
at on in 都不见。