Think about / Think of
The two most common prepositions used after the verb “think” are “about” and “of.” They are very similar, but there is a small difference. Usually when you “think of something,” it is a brief moment – just a few seconds. It is also used for opinions. When you “think about something” you are considering it for a longer time – like a few minutes or more.
Every time I hear this song, I think of my mother.
(thinking for a few seconds)
What do you think of my new haircut?
I’m thinking about moving to a different city.
I still get angry when I think about all the rude things my sister said to me.
(thinking for a few minutes or more)
Common error: Don’t use “think to” for “considering.”
I’m thinking to do an intensive English course in Canada.
I’m thinking about doing an intensive English course in Canada.
Think over / Think through
Use the prepositions “over” and “through” when you need to consider a topic carefully or think about it for a longer time (hours, days, or weeks).
I’m not sure which course I want to take. Let me think it over for a while.
I’ll need some time to think through your proposal. Can I call you back next week?
Think ahead / Think back
The preposition “ahead” is used for thinking about the future:
We need to think ahead at least five years if we want our company to have long-term success.
The preposition “back” is used for thinking about the past:
I like to think back on my college years; that was a great time in my life.
“Think up” is an expression that means to imagine, invent, or create an idea.
We need to think up a way to distract Laura while we plan her surprise party.
I spent half an hour trying to think up a good excuse for why I was late to work.
Let’s think up some new strategies for increasing sales.
“Think to” is most frequently used with “myself” – when you think about something, but you don’t say it or share it with any other person. “Think to myself” is often followed by a direct statement of the thought.
Whenever I’m in a meeting at work, I think to myself, “This is a huge waste of time.”
“Didn’t think to” can also be used when something did not even enter your mind.
Sorry I didn’t see your message – I didn’t think to check my e-mail before I left the house.
I’m annoyed because all my friends went to the movies and didn’t think to invite me.