See, saw, seen are three forms of the same verb and they show time: present, past, and past participle. Use see for now and habits, saw for finished past time, and seen after auxiliary verbs like have or be. Choosing the right form depends on whether you are using a simple tense or a perfect or passive structure. Mastering these forms helps you speak and write with correct tense and grammar.

See is the base form and the present tense form used with I, you, we, and they. It also appears after modal verbs like can, will, should, and must, and after to in the infinitive. Use see when the action is general, habitual, or happening in the present depending on context and other words in the sentence.

In the simple present, see changes only in the third person singular: he, she, it. Most subjects use see, but he, she, and it take sees. This is about subject-verb agreement, not time, so it applies even when you talk about routines and facts.

Subject	Form	Example
I	see	I see your point.
you	see	You see the problem.
he	sees	He sees the sign.
she	sees	She sees the difference.
it	sees	It sees movement.
we	see	We see the results.
they	see	They see the change.

Saw is the simple past form. Use saw for actions that happened and finished in the past, often with past time words like yesterday, last week, in 2020, or earlier. Saw does not change with the subject, so it is the same for I, you, he, she, it, we, and they.

Subject	Form	Example
I	saw	I saw her yesterday.
you	saw	You saw the notice.
he	saw	He saw the email.
she	saw	She saw the show.
it	saw	It saw a shadow.
we	saw	We saw the sunset.
they	saw	They saw the mistake.

Seen is the past participle form. You do not use seen alone as the main verb in standard English. Seen needs an auxiliary verb, most commonly have for perfect tenses or be for passive voice, to form a correct verb phrase.

Use have plus seen to talk about experience, completed actions with present relevance, or actions up to a time in the past. Choose have or has in the present perfect, and had in the past perfect. In these structures, seen never changes, only the auxiliary changes.

Subject	Form	Example
I	have seen	I have seen that movie.
you	have seen	You have seen the report.
he	has seen	He has seen the update.
she	has seen	She has seen the message.
it	has seen	It has seen heavy use.
we	have seen	We have seen improvement.
they	have seen	They have seen the changes.

Use be plus seen to focus on the thing that is observed instead of the person who observes. The auxiliary be changes for tense and agreement, while seen stays the same. This is common in formal writing, reports, and situations where the observer is unknown or unimportant.

Rule	Example
Use be plus seen for passive meaning	The suspect was seen near the station.
Change be for time and subject	The sign is seen from far away.
Add by to name the observer when needed	The comet was seen by many people.

In simple present and simple past, questions and negatives use do, does, or did plus the base form see. Do-support carries the tense, so the main verb stays see, not saw or seen. In perfect tenses, questions and negatives use have or has plus seen, not do-support.

Rule	Example
Present questions use do or does plus see	Do you see it.
Present negatives use do not or does not plus see	She does not see the issue.
Past questions use did plus see	Did they see you.
Past negatives use did not plus see	I did not see it.
Perfect questions use have or has plus seen	Have you seen my keys.
Perfect negatives use have not or has not plus seen	He has not seen the email.

These forms appear in very common structures that signal which form to choose. After modals, use see. After have, use seen. For reported observations in the past, saw is common with a finished time reference. Learning these patterns helps you choose quickly without translating.

Rule	Example
After modals use see	I can see the answer now.
After to use see	I want to see it again.
After have use seen	We have seen enough.
Finished past time uses saw	We saw it last night.

In some dialects and informal speech, people may say seen as a simple past form, like I seen it. In standard written English and most formal spoken English, this is considered incorrect. For standard usage, use saw for the simple past and reserve seen for structures with have or be.