research と investigate と inquire と look into はどう違いますか？説明が難しい場合は、例文を教えて下さい。

Research is to learn, gain knowledge, and draw facts about something. It is often used in science and school for studying purposes.

Investigate is to find out what happened with something or somebody. It is often used in situations where there's a problem like crimes or a dispute.

Inquire means you want to know more information about something or somebody. It doesn't have to be as intense as an investigation or research, but you just want to know more about it before making a decision.

'Look into' is when you want to determine and understand the accuracy, condition, or quality of something. The key word is to understand. For example, you are confused by what is happening at work, so you might check on it to understand what's going on.