I (travel) to Thailand last year.
+: I travelled to Thailand last year. - : I didn't travel to Thailand last year ?: Did you travel to Thailand last year?
We (oversleep and miss) our train.
+: We overslept and missed our train - : We didn't oversleep and didn't miss our train. ?: Did you/we oversleep and miss our/your train?
They (get on) a bus at the Central Station and (get off) in the city centre.
+: They got on a bus at the Central Station and got off in the city centre. - : didn't get on / didn't get off ? : Did they get on and did they get off?