This book (made by a Korean) says you have to use 'since' or 'for' with present perfect, so you can't use 'for' with past simple. Seriously? ಠ‸ಠ (I'm confused)
He [worked / has worked] at the same company for 10 years.
The answer is 'has worked' and that means he worked 10 years ago and he is working now.
In this sentence, is the past simple [worked] wrong grammatically?
How about this situation:
He worked at the same company but does not work now. In this case, is
He worked at the same company for 10 years
still wrong? If so, how can I say that?