What is the present subjunctive form of the verb to know?

know

The present subjunctive form of a verb looks just like the bare infinitive.

Thank you.

However, I heard "I wish I know" is incorrect and the correct form was "I wish I knew". Why is that?

Because you need the past subjunctive after "I wish".

Whereas the present subjunctive is identical in appearance to the bare infinitive, the past subjunctive is identical in appearance to the simple past.*

CJ

*except for the verb to be, which has the past subjunctive were in all cases.

Thank you.

Does the same rule apply after "I think"?

No, it doesn't.

Thank you