a. I didn't realize that you were a cop. or b. I didn't realized that you were a cop.
closed as off-topic by Bradd Szonye, anongoodnurse, Brian Hooper, David M, choster Mar 11 '14 at 15:22
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "Questions that can be answered using commonly-available references are off-topic. A list of these references can be found here: List of general references" – Bradd Szonye, anongoodnurse, Brian Hooper, David M, choster
(a) is definitely correct.
"realized" is the past tense of "to realize".
I did not notice that you... I did not see that you... I did not realize that you... I did not forget that you...
Try changing the words highlighted in bold to the past tense and see if they make sense to you.
When two (or more) verbs come one after the other like this in English, the second verb must be an infinitive ("to notice" or "notice") or a participle ("noticing", "noticed"). Only the first verb is conjugated.
- I didn't notice
- I am noticing
- I hadn't noticed
- I don't like | eating vegetables
- I have stopped | trying | to understand