What is the difference between a main topic and an opinion? Students often ask this in my TOEFL classes and in my essay classes. Many think they are the same. Actually, there is a difference - a big difference. Look at the two sentences below.
A. I think California was the best trip ever.
B. I think California was the worst trip ever.
In sentence A, the writer will write about California. California, therefore, is the main topic (also called the main idea or main subject). The writer's opinion is “…was the best trip ever.”
In sentence B, the speaker will speak about California. Once again, California is the main topic. However, the speaker's opinion is “…was the worst trip ever.”
As you can see, the main topic (California) is the same in both sentences. However, the writer and the speaker express different opinions about California (best trip vs. worst trip).
Technically, California in both sentences is the main topic while the opinions are the controlling ideas. A controlling idea is what the essay is about, for example:
A. I think California (main topic) was the best trip ever (opinion-controlling idea).
In this essay, the writer will give positive examples to support her opinion.
B. I think California (main topic) was the worst trip ever (opinion-controlling idea).
In this argument, the speaker will give negative examples to support his opinion.
A fast and easy way to identify the controlling idea in an argument is to ask this question: "What about it?" For example, look at the premise of a fact-based essay below.
The great white shark is an apex predator.
The main topic of this fact-based essay will be "The great white shark." Controlling idea = What about it (the great white shark)? It is an apex predator = controlling idea.
The great white shark (main topic) is an apex predator (controlling idea).
Next, look at this thesis from an opinion-based essay.
Personally, I think Californian wine is the best in the world.
Main topic = Californian wine. What about it? (It) is the best in the world = controlling idea.
Want to learn more TOEFL writing strategies or how to write opinion-based and fact-based essays? It's all in Speaking and Writing Strategies for the TOEFL iBT.
My new text - Scoring Strategies for the TOEFL iBT A Complete Guide - will be published this summer.
The Pro
© Bruce Stirling 2011
