Could I use present perfect tense with "in the 1990(specific year)"?
And, what about "in the 1990's"?
I was taught not to use specific past adverbs with present perfect...
But, I have seen those adverbs with present perfect tense.
So, I'd like to know if it is gramatically right, or wrong?
"in 1990" (a specific year) isn't compatible with the present perfect. As for "in the 1990s" (a period of time) I can't seem to think of a single example that works with the present prefect. Would you be willing to provide us with a few of the examples you've come across?