Reason
There is so much information today that it is not easy to keep up to date. We therefore trust in others to summarize the most important facts for us.
Try to recall how often you summarize something, e.g. when you're telling your friends the plot of the latest movie, when you are asked to give in brief the main points of a text you've read.
Preparation
First of all, you should have read the text / watched the film (of course). Make notes of the most important facts.
Structure and Content
- Introduction - Give a brief overview.
- Content - Tell the main points of the plot / content in your own words.
Important Tenses
The most important tense for a summary is the simple present. Actions happening one after the other are in simple present. Note, however, that you have to use different tenses for everything happening at the same time or before.
Some summaries are written in simple past. This is the case for example when summarizing newspaper articles.
Note
Leave out unimportant details. Always check your notes and only use details in your summary that are really essential for the plot.
Examples
At www.awerty.com you'll find examples for summaries on novels. Just read a few of them and make a list of useful phrases that you may want to use in your summaries.
A commentary is not usually part of a summary.