There are 2 sentences that I'd like to prepare.
I have heard recommendations from doctors.
I heard recommendations from doctors.
I think sentence 2 is wrong because 'recommendations' is plural and that is compatible with present perfect tense used to talk about several different actions which have occurred in the past at different times. However, past tense is more compatible with an action that occurred once before. So, I think it would be more suitable to put sentence 2 like a following.
I once heard a recommendation from a doctor a couple of days ago.
I'd just like to make sure that I use each tense properly.
So, could you let me know if I'm right to think this way?