Choose the correct answer.

It's difficult ....................... chess well. a) playing b) to playing c) to play
I'm determined ..................... my exams. a) passing b) to passing c) to pass
I apologize ...................... at you. a) shouting b) for shouting c) for shout
We're looking forward ......................... on holiday. a) going b) to going c) to go
It's dangerous ....................... in that river. a) swimming b) to swimming c) to swim​