1. Introduction的作用：
An introduction is crucial, not just for what it says about the topic, but for what it tells the reader about writer”s style and approach. Unless you can introduce the subject clearly the reader may not wish to continue.
For a relatively short essay written under exam conditions, the following are worth including, in this order.
a. Definitions of any terms in the title those are unclear
b. Some background information
c. Reference to other writers who have discussed this topic
d. Your purpose in writing and the import
