I Thought?

Hi New2grammar

It should be I thought I knew.

I think I know the answer.

I didn't know you were here. (You are surprised to see that person at that place.)

Thanks YoongLiat for confirming that.
Come to think of it, it could have been just a typo. Afterall,
the difference is only one letter. I've made more severe typos.

The bottom line is, a learner (even for me) may have a hard time deciding if it's a singular or plural verb agreement, even though I thought I know!

Hi,

I think there is more to it than it just being a typo.

I think you can use 'I thought I knew' and 'I thought I know' under different circumstances. I think with 'I thought I know', the event and knowing is more current and up-to-date... and related to the current situation. Whereas, with 'I thought I knew', the event and his/her knowing are all in the past.

1. Jim, do you know how to make this?

I thought I know how to make that but apparently I don't.

2. Jim, why didn't you make that yesterday?

I thought I knew how to make it but I didn't. Sorry.

I wrote those examples but am not sure they make much sense (even to myself). I would like to know more myself. It would be nice to get some help.

Actually, I didn't think I was a typo either so I created this thread.
But after YL replied, it thought it could have been a typo since the difference is only one
character. Well, I guess we need more confirmation. Maybe it's matter of style. It could be
grammatically incorrect but idiomatic to native speakers. I don't know. We'll see.

New2grammar
What's the difference between "I thought I knew" and " I thought I know"?

I was told that the verb following "I thought" must be past tense.

Could a native speaker please respond to New2grammar's query?

Many thanks.

I'm not a native speaker but I am pretty sure the version with the present tense "I though I know" sounds quite odd. You could hear something similar when "I know" is reported as direct speech, or is not really linked to "I thought":
There was this girl, you know, and... like, I thought, "I know her... I'm pretty sure I know her", you know, I had that weird feeling.

But I'm sure that's not what you meant. In non-broken speech, you need to use the past tense after verbs like thought, didn't think, felt, knew, etc. Verbs like those seem to force a backshift in tense because they are more related to your "feelings" at a certain moment in the past than the "information" you had or got.
Oh, so you are American? I thought you were Canadian! I didn't know you were from Florida.

Hi Kooyeen

I agree with you completely, and the following example is excellent.

Oh, so you are American? I thought you were Canadian! I didn't know you were from Florida.

However, New2grammar and Believer are not convinced that I've provided them with the correct reply.

That's why I believe that a native speaker's authoritative reply will convince them.

New2grammarWhat's the difference between "I thought I knew" and " I thought I know"?

I was told that the verb following "I thought" must be past tense.

Kooyeen has the answer:

you need to use the past tense after verbs like thought, didn't think, felt, knew, etc. Verbs like those seem to force a backshift in tense because they are more related to your "feelings" at a certain moment in the past than the "information" you had or got

Memorize:
I thought I knew / I thought I had to / I thought I was / I thought they were / I thought I could / I thought they would / ...
I knew I had to / I knew I was / I knew they were / I knew I could / I knew they would / I knew they wanted / ...
I felt I knew / I felt I had to / I felt I was / I felt they were / I felt I could / I felt he would / ...
I hoped I was / I hoped they were / I hoped I could / I hoped I didn't have to ...
I believed I knew / I believed I could / I believed they were / I believed I was / ...
I didn't think ... / I didn't know ... / ... / Did you know ...? / Did you feel ...? / ... (same for negations and questions)
Adding that doesn't change the basic principle here: I thought that I knew ...
___________

And don't attempt to use present tense after thought, knew, felt, hoped, or believed -- and you'll be fine. You'll sound just like a native speaker.
But put a present tense there (I knew they are / I thought I am / I hoped I can / ...), and you'll expose yourself immediately as a non-native!!!
CJ
P.S. If you make a distinct pause in speech to indicate a direct quote, these principles do not apply:
I thought, "I know how to do that. Why are they saying I don't?"
I thought [ short pause ] I know how to ...
You absolutely cannot use the complementizer that in this case:
*I thought [ short pause ] that I know how to ... (NO!)