1：介词能使词语更加精练.例如：

1)当我听到这事时，我简直不敢相信我的耳朵.

A：I couldn’t believe my ears when I heard this .

B: I couldn’t believe my ears at this .

2)麦克是个矛盾的人

A：mike is a man who has contradictory ideas.

B:mike is a man of contrasts.

3)她走后留下六个孩子

A:she left six children after she died.

B:she left six children behind her.

4)如果需要帮助，就给我打电话，号码是7145330

A:if you need help, just ring me up . my telephone number is 7145330

B: If you need help ,just ring me up at 7145330.

5)我们举杯庆祝他的成功.

A:we raise a toast to congratulate him on his great success.

B:we raise a toast to his great success.

2:介词能使语言更加生动形象.例如：

6)这篇文章生词太多，我要理解真是太难了.

A：There are so many new words in this passage, so it is hard for me to understand .

B:with too many new words in it , this passage is beyond me .

7)他因为20票之差输了竞选.

A：He misses election because of 20 votes.

B:He missed election by 20 votes.

8)证据对他不利.

A:The evidence is not good for him .

B:The evidence is against him.

9)给他一杯咖啡，钱算在我身上.

A:Please him a cup of coffee,I will pay for it .

B:Please him a cup of coffee on me .

10)他现在已经60多岁了.

A:He is more than 60 years old now .

B:He is over 60 now .

比较A与B，我们会惊叹介词有如此的魅力与表现力.B中出现的at,of,by,on,over,with等都是常见的介词，它们在句中不仅使语言更加精练，而且形象更加生动，小小的介词真真起到"画龙点睛"的作用.