2. Past Simple or Present Perfect?

a. My geography teacher has travelled to almost all Asian countries. b. My father has bought a new car. It's really fast and showy! c. The box is empty! Someone has eaten all the sweets! But I bought three packs of candies last Sunday. Look in the cupboard, there must be some left. d. Last week my dog ran away but some people have seen him recently and I hope we'll find him soon.