Cohesive Device for Contrasting

My friend did her homework last night,......................, I did not. (however / yet)

. People say that restaurant is great,................. I didn’t like the food there. (whereas / yet)

Australia is surrounded by water on all sides,..........Bolivia is surrounded by land. (whereas/however)

. I prefer chocolate cakes for dessert,..................my brother prefers vanilla ice cream. (whereas / yet)

The players were tired after the football game,...........none of them could fall asleep. (yet / whereas)