4.序数词的用法：
序号 用法特点 举 例
1 前面要加the Hes always the first to get to meeting-room.
2 前面用a/an表又一，再一 Hed better try a fourth time.
介词
1.介词的概念及分类：介词是一种虚词，不能单独在句中充当成分，要与宾语一起构成介词短语才可在句中充当成分。介词按形式分为简单介词、复合介词、短语介词、特殊介词和双重介词。
分类 例 词
按形式分
简单介词 at， about， above， after， as， but， by， down， during， except， for， from， in， like， near， off， of， on， opposite， over， past， round， since， through， till， to， under， until， up， besides， between， beyond， with， across， against， along， among， around， before， behind， below， beside
复合介词 inside， outside， onto， into， toward， upon， within， without
短语介词 along with， together with， according to， ahead of， as for， as to， because of， due to， except for， owing to， out of， up to， by means of， by the side of， by way of， in front of， in spite of， as far as
特殊介词 concluding， regarding， considering， save
双重介词 until after， until before， Saturday， except， on duty
按功能分
空间（地方、位置、方向、范围、界限、包括、排除） about， above， across， after， against， along， among， round， at， before， behind， with， below， beneath， beside， besides， between， upon， save， beyond， but， by， concerning， down， on， out of， outside， over， past， through， throughout， towards， under， up
时间 after， before， as， between， by， during， for， from， in， on， over， past， till， until， up to， within， through， throughout
原因理由根源（目的，内容等） about， according to， as， because of，due to，owing to，on acount of， from， of， on， with， regarding， concerning， considering， through， by， under， for
2．容易混淆的介词：
区别讲解 例句 :
表 时 间 的 介 词 at， on， in at表示在几点几分（单位最小）；on表示在具体的某一天或某天上午（下午晚上等）；
in表示在几天、周、月、年。 I get up at six oclock.
It happened on a spring morning.
There are seven days in a week.
in the morning / evening / afternoon；at noon / night / dawn / sunrise / sunset / lunch / dinner / supper， etc.
during， for， in for后加一个表时间段的具体单位（常用复数）；during强调持续或某活动期间；in指在一段时间内。 She has lived here for six years.
He was in English during the war.
In those days he was poor.
till， until till/until构成的短语修饰持续性动词，非持续性动词要用否定式。 They waited till/until 10:00.
They didnt leave until/till 10:00.
after， since after+时刻或时段，ll be back after eight oclock.
Shes lived here since 2002.
in， after in+时段，ll leave after 11:00.
He left after 11:00.
She left after a few hours.
Shell be back in half an hour.
表 空 间 位 置 及 方 向 方 位 的 介 词 at， on， in at指一个点或小地方；
in指一个地区或大地方空间内；on在某一平面或线上面。 They arrived at the village at ten.
Your pencil is in the desk.
Your pencil is on the desk.
on， above， over on与物体接触反义词为beneath；over在s a book on the desk and a pen beneath the book.
Theres a lamp over the desk and a bag under the table.
Jacks bedroom is above mine on the second floor.
over， across， through across表面跨过；
through从中间或从头至尾穿过；
over从上空越过。 Hes swimming across the river.
They walked through the forest.
A plane is flying over the city.
at， beside， by， next to， near at靠得最近；
beside在并排一条线上；
by在并排一条线上；
next to在顺序上紧靠旁边；
near 靠得最远，不表明确方向或顺序。 Lets meet at the school gate.
The building beside the library is the shopping center.
The boy standing by my side is from Shanghai.
Whos sitting next to/beside Mr.Steve?
about， round， around. about表示周围是随意的，不规则的；round或around的周围则是较完整的一个圈。 Dont leave the toys about the meeting-room.
They are sitting round/around the table.
to， for， at to 运动的方向，目的地；
for 动身出发的目的地；
at 有意攻击的目标。 Throw it to me.
Hell leave for Shanghai.
He threw the ball at that boy.
up， down up指往上，往北，大地方，靠拢；
down指向下，往南，向小地方，往开走但在一市区，去中心区用down，去郊区等用up。 They are going up the hill.
They are going down river.
Im going down town shopping.
on， in， to in表在某地区内；
on表接壤；
to表在某地区以外。 Shanghai is in the south of China.
Hunan lies on the north of Guangdong.
Xichang lies to the south west of Chengdu.
between，among between指两者之间；
among指在三者以上之间。 Theres a river between the two villages.
Theres a small house among the trees.
besides
except
except for
except that
but
but for besides除t know Peter except that hes an Japanese.
Theres nothing but a chair in the room.
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