I don’t see how to handle sequence of tenses.
He knows that the earth is round.
He knew that the earth is round.
I can understand the above two sentences. How about the following two sentences?
(a) I know he is fine.
(b) I knew that he is fine.
Generally speaking, I think that sentence (b) should be amended into “I knew that he was fine”, because tenses (knew and is) don’t match; however, If he is fine now, can I say “I knew that he is fine” to express that he is fine even now?
I want to know more about exceptional cases of sequence of tenses.
We know this is true because we can actually report the speech with a direct quotation. We choose according to what we want to say, not according to fictitious rules.