think

If you think that something is or may be true, you feel that it is or may be true.

Example: You know you can't do that. What were you thinking?

If you think about something, you use your mind to give it your attention.

Example: "What's the best way?" "I'm not sure. Let me think."

You use think when you have words or ideas in your mind without saying them out loud.

Example: "It's no good," she thought.

You use think in suggestions and requests.

Example: I was thinking we could go out tonight.

If you don't think to do something, you don't remember to do it.

Example: I didn't think to ask her.