Present Perfect, Present Continuous, Present Perfect Continuous

My classmates... already... (to know) some amazing facts about Ukrainian sportsmen.

They... (to play) volleyball for an hour.

Bill... (to play) baseball at the moment.

The children... just... (to discuss) this problem with their parents.

Dan and Tom... (to train) at the stadium now.

The boys... (to watch) the football match for forty minutes.

My uncle and my father are in the Sports Palace now. They... (to watch) the hockey match.

John can`t participate in the competition because he... just...(to break) his arm.

Clark... (to walk) in the park for half an hour.

Mrs Brown... already... (to explain) grammar rule.

Mrs Brown... (to explain) grammar rule for 10 minutes.

My mother... (to cook) delicious meal for birthday party now.