I swam yesterday.Did you swim yesterday? No,I didn't.
She went to the cinema.Did she go to the cinema last week? Yes,she did.
They were at home last Sunday.Were they at home last Sunday? No,they weren't.
He rode a bicycle last summer.Did he ride a bicycle last summer? Yes,he did.
We studied Chemistry last year.Did we study Chemistry last year? No,we didn't.