英语中，介词是英语基础知识中较为庞杂的体系。介词的用法也是英语运用过程中的常见项目。莱曼英语认为，英语中的介词好读，好认，好写，好记，但不好用。有些中学老师曾说过，如果一个学生的英语仍然不及格，那么，就突击将介词的用法掌握住，就会自然和必然地及格了。此话一语中的，说明介词非常的重要。
根据莱曼英语的归纳和总结，介词的基本用法可分为下列五类：
一.随意词组
二.固定词组
三.动词+介词句型
四.be +形容词+介词句型
五.be +介词词组
通过系统的学习，并加上一定的练习，介词将对英语学习的近期目标——考试，以及长期目标——交流起到极大的促进作用。这其中，对于庞杂的介词项目的记忆是关键所在。莱曼英语倡导一学二记三运用，针对介词而言，其中的第二步甚为重要。
首先，我们先来看看英语中都有哪些常用介词：
1.in 2.on 3.under 4.behind
5.at 6.of 7.after 8.between
9.off 10.to 11.with 12.around
13.as 14.by 15.over 16.below
17.about 18.without
19.above 20.before
21.into 22.onto
23.like 24.unlike
25.for 26.beneath
27.from 28.among
29.along 30.within
31.during 32.beside
以上常用介词均不单独实用，而是与其它词类搭配使用，从而构成无数的词组和句型，形成英语语法中一道独特的风景线。同时，永远不要忘记介词之后必须跟名词，代词宾格以及动名词，或跟及从句，这是英语基本规律，是任何英语学习者应该知道的，自然，也是英语考试题中的基本分数题。
一.随意词组
所谓随意词组就是在任何介词之后加上名词,代词宾格或动名词,即可构成一个词组。如：
1.in the room 2.in the box
3.on the table 4.on the chair
5.at the bus-stop 6.at the crossing
7.under the desk 8.under the sofa
随意词组人人可造，并不难。由于简单，所以不作为考试的重点。
二.固定词组
英语中介词的固定词组是英语语言不断发展过程中慢慢演变而成的,是难以更改的。充其量可更改其中的宾语。因而，介词的固定词组就成了英语学习中必背的诸多内容之一，也是英语考试中考核的重点内容之一。莱曼英语建议大家本着一学，二记，三运用的原则去驾驭和掌握介词固定词组这一语法项目。
1.in 的固定词组：
(1)in English (2) in red
(3)in turn (4) in ink
(5)in return (6) in 1987
(7)in spring (8) in March
(9)in the morning (10)in line
(11)in front of (12)in the front of
(13)in a hurry (14)in need of
(15)in the tree (16)in use
(17)in the sun (18)in touch with
(19)in time (20)in no time
(21)in cash (22)in trouble
(23)in the east (24)in the end
(25)in a low voice (26)in the middle of
(27)in charge of (28)in a word
(29)in thirties (30)in one's twenties
(31)in the face (32)in the corner
(33)in surprise (34)in advance
(35)in 3 days (36)in this way
(37)in addition to
2. on 的固定词组：
(1) on Sunday (2) on duty
(3) on Christmas (4) on one's birthday
(5) on one's way to(6) on the tree
(7) on the left (8) on the east of
(9) on foot (10)on behalf of
(11)on time (12)on and on
(13)on business (14)on leave
(15)on the back (16)on watch
(17)on the corner (18)on purpose
(19)on the contrary(20)on the opposite of
(21)on show (22)on sale
(23)on December 5th
3. at 的固定词组：
(1) at night (2) at noon
(3) at home (4）at the crossing
(5) at sis o'clock (6) at half past six
(7) at 6:30 (8) at a quarter to six
(9) at the end of (10)at the beginning of
(11)at the top of (12)at least
(13)at last (14)at the corner of
(15)at school (16)at work
(17)at the speed of(18)at the temperature of
(19)at first (20)at 6:00 sharp
(21)at the foot of
4. of 的固定词组：
(1) first of all (2) because of
(3）all of (4) one of
(5) some of (6) many of
(7) none of (8) a lot of
(9) lots of (10)a piece of
(11)a pair of (12)a great deal of
(13)a great deal of(14)a great amount of
(15)plenty of (16)all of a sudden
(17)out of control (18)out of...
(19)in front of (20)in the front of
(21)of one's own (22)as the matter of fact
(23)of course (24)hundreds of
(25)thousands of (26)a pile of
(27)a map of China (28)certain amount of
(29)in need of (30)in name of
5. by 的固定词组
(1) by the way (2) by bus
(3) by bike (4) by ship= by sea
(5) by taxi (6) by plane= by air
(7) by subway (8) by train= by railway
(9) by the end of (10)by chance
(11)by oneself (12)by means of
(13)step by step (14)by the river side
6. after 的固定词组
(1) after all (2) after 3 days
(3) after you (4) after class
(5) after school (6) after work
(7) after me (8) the day after tomorrow
(9) day after day (10)one after another
7. with 的固定词组：
(1) with one's help (2)with the help of
(3) with a pen (4)with a smile
8. as 的固定词组
(1) as well (2) as...as
(3) as a student (4) as long as
(5) as if (6) as soon as possible
(7) as soon as (8) as a result
9. about 的固定词组
(1) about grammar (2) about 6 feet long
(3) about 30 people
10. from 的固定词组
(1) from...to.. (2) far from
(3) different from
11. for 的固定词组
(1) for example (2) for instance
(3) for a long time (4) for time being
(5)except for...
有关介词的其他用法将在莱曼英语介词基础知识第二讲中进行介绍，含：
1.动词 + 介词句型
2.be + 形容词 + 介词句型
3.be + 介词词组句型