Поставить в нужную форму, в зависимости от conditional'а
1-а
2-с
3-b или с
4-а или с
Mark can play the piano
Mark can climb a tree
Mark can’t ride a horse
Mark can’t use a computer
Sally can’t play the piano
Sally can climb a tree
Sally can ride a horse
Sally can’t use a computer
Peter can’t play the piano
Peter can’t climb a tree
Peter can ride a horse
Peter can use a computer
Brian can play the piano
Brian can climb a tree
Brian can’t ride a horse
Brian can use a computer
Meg can’t play the piano
Mag can’t climb a tree
Mag can’t ride a horse
Mag can use a computer