Past Simple : (1) This tense denotes an action completed in the past as in : in 1980, in May, on Monday, at 10 a.m etc. We can mention the exact time when the action took place .
- He went to Delhi yesterday.
- They ate up all the mangoes we had kept in the basket.
- When did you see him last?
- Did he lose his key? Yes he did.( whether he got back the key now or not is not mentioned/clear here)
- What did you say when he came to quarrel with you?
- I didn’t have any money with me to help you.
- He completed the work single-handed before schedule.
(2) We use past tense (Not present perfect) if there is no connection with the present( for example , things that happened a long time ago)
- Chinese invented printing. (Not ‘have invented ‘)
- How many plays did Shakespeare write? ( Not ‘ has Shakespeare written’)
- He is a historian. He has written many books on his subject. ( He still writes books, he is still alive. In this context, we use ‘ present perfect ‘ instead of past.)