If you think that something is the case, you have the opinion that it is the case.

If you say that you think that something is true or will happen, you mean that you have the impression that it is true or will happen, although you are not certain of the facts.

If you think in a particular way, you have those general opinions or attitudes.

When you think about ideas or problems, you make a mental effort to consider them.

If you think in a particular way, you consider things, solve problems, or make decisions in this way, for example because of your job or your background.

If you think of something, it comes into your mind or you remember it.

If you think of an idea, you make a mental effort and use your imagination and intelligence to create it or develop it.

If you are thinking something at a particular moment, you have words or ideas in your mind without saying them out loud.

If you think of someone or something as having a particular quality or purpose, you regard them as having this quality or purpose.

If you think a lot of someone or something, you admire them very much or think they are very good.

If you think of someone, you show consideration for them and pay attention to their needs.

If you are thinking of taking a particular course of action, you are considering it as a possible course of action.

You can say that you are thinking of a particular aspect or subject, in order to introduce an example or explain more exactly what you are talking about.

You use think in questions where you are expressing your anger or shock at someone's behaviour.

You use think when you are commenting on something which you did or experienced in the past and which now seems surprising, foolish, or shocking to you.

You can use think in expressions such as you would think or I would have thought when you are criticizing someone because they ought to or could be expected to do something, but have not done it.

You can use think in expressions such as anyone would think and you would think to express your surprise or disapproval at the way someone is behaving.

You use expressions such as come to think of it ,when you think about it, or thinking about it, when you mention something that you have suddenly remembered or realized.

You use 'I think' as a way of being polite when you are explaining or suggesting to someone what you want to do, or when you are accepting or refusing an offer.

You use 'I think' in conversations or speeches to make your statements and opinions sound less forceful, rude, or direct.

You say just think when you feel excited, fascinated, or shocked by something, and you want the person to whom you are talking to feel the same.

If you think again about an action or decision, you consider it very carefully, often with the result that you change your mind and decide to do things differently.

If you think nothing of doing something that other people might consider difficult, strange, or wrong, you consider it to be easy or normal, and you do it often or would be quite willing to do it.

If something happens and you think nothing of it, you do not pay much attention to it or think of it as strange or important, although later you realize that it is.