It is quite easy for us to remember the basic meanings of those common words. However, it will take us a long time to command their usages.

Take the word "sick" as an example.

You may homesick because you have been away from China for such a long time.

You may carsick. Interestingly enough, some carsick people have no problem in driving the car, because their attention are focused on the driving...

There are a lot of work to do in your company recently. You really got bored. Well, I give you a suggestion. Tomorrow moring, just call sick.
Tell your manager you are sick.....