Have you ever started talking about a topic and then suddenly, you were telling a story that turned out to be unrelated to your main point? I have!
This happens in TOEFL lectures too! TOEFL professors are talking about one thing and then, they get slightly off their main topic. They may start telling a story or talking about other issues. What they are say is still somewhat related to the main idea, but it is not the main idea! And this is what is important for students to notice: the difference between the main idea of the lecture and a digression from the main idea.
To digress (v) means to leave the main topic for a short time. Digressions (n) can also be called tangents. The professor gets side-tracked.
Main ideas are like main roads. They are clear and easy to follow.
But, then, while you are driving down the main road, you decide that there's something on the side you have to see. You drive the car off the main road onto a side road.
This is the tangent.
You might be taking lots of pictures along the side road. You might be taking notes on the tangent in TOEFL. But then, you must eventually realize that this is a tangent and NOT the main idea.
The TOEFL will ask for the main idea. So, how do we know what it is? Well, eventually, the professor must return to the main road and the main idea. To get back, you will hear the professor say something like the following:
“Well… anyway… the question for us is...”
Or
“But I digress. The main thing here is...”
Or
“But I don’t want to get into that now. What we need to look at is…”
Or
"But that's another matter. The key thing for us to consider is..."
When you hear this (or something similar), you now know all those notes you just took are NOT the main idea. So, you can put them aside. But, that doesn’t mean you won’t get a question about them. There may be a question that asks why the professor mentioned a particular item that came up in that section. The correct answer choice will include the idea that the professor digressed.