Topic sentences are important
For cohesion and coherence, band score 7, you need to persuade the examiner that you have a clear central topic in each main body paragraph.
A good topic sentence makes it easy for the examiner to see your clear central topic.
Before looking at a simple topic sentence, it's important to understand where the topic sentence goes and what its role is in a paragraph.
The topic sentence should be the first sentence in your paragraph. The examiner wants to see a topic sentence, so don’t disappoint him.
The topic sentence should do two jobs. One is compulsory, and the other is optional but desirable.
What two things should the topic sentence tell the examiner?
Your default topic sentence
What is your default topic sentence?
What will you write if you can’t think of anything better?
Take a typical IELTS Task 2 question:
So obviously, paragraph 1 is about the reasons why people change their jobs.
Two default topic sentences
There are two main reasons why [...]
People tend to [...] for two main reasons
There you have two topic sentences. You could adapt them to many different main ideas. Here are some examples:
There are various reasons why obesity is on the rise.
There are three main reasons why people who like change in their lives tend to change jobs more frequently.
People change their jobs for various reasons.
Online shopping is advantageous to consumers for two main reasons.
There is one main reason why raising the price of petrol will reduce traffic congestion.
Not all paragraphs are about reasons.
If you're writing main body 1 for the question above, your paragraph is not about reasons; it's about areas of progress. You could adapt the technique from above like this:
There are two main areas in which mankind has made progress.
Mankind has made great progress in two main areas.
Of course, it would be easily to name the areas of progress:
Mankind has made great progress in two main areas, namely technology and healthcare.
All the topic sentences shown above would be perfectly good topic sentences for writing Task 2.
In the next post I'll show you how to improve them.