I can climb you can climb he can climb we can climb you can climb they can climb
V-ing form
I can be climbing you can be climbing he can be climbing we can be climbing you can be climbing they can be climbing
Perfect
I can have climbed you can have climbed he can have climbed we can have climbed you can have climbed they can have climbed
V-ing perfect
I can have been climbing you can have been climbing he can have been climbing we can have been climbing you can have been climbing they can have been climbing
Negation
Simple form
I can't climb you can't climb he can't climb we can't climb you can't climb they can't climb
V-ing form
I can't be climbing you can't be climbing he can't be climbing we can't be climbing you can't be climbing they can't be climbing
Perfect
I can't have climbed you can't have climbed he can't have climbed we can't have climbed you can't have climbed they can't have climbed
V-ing perfect
I can't have been climbing you can't have been climbing he can't have been climbing we can't have been climbing you can't have been climbing they can't have been climbing
Interrogative form
Simple form
can I climb? can you climb? can he climb? can we climb? can you climb? can they climb?
V-ing form
can I be climbing? can you be climbing? can he be climbing? can we be climbing? can you be climbing? can they be climbing?
Perfect
can I have climbed? can you have climbed? can he have climbed? can we have climbed? can you have climbed? can they have climbed?
V-ing perfect
can I have been climbing? can you have been climbing? can he have been climbing? can we have been climbing? can you have been climbing? can they have been climbing?
Interro-negative form
Simple form
can't I climb? can't you climb? can't he climb? can't we climb? can't you climb? can't they climb?
V-ing form
can't I be climbing? can't you be climbing? can't he be climbing? can't we be climbing? can't you be climbing? can't they be climbing?
Perfect
can't I have climbed? can't you have climbed? can't he have climbed? can't we have climbed? can't you have climbed? can't they have climbed?
V-ing perfect
can't I have been climbing? can't you have been climbing? can't he have been climbing? can't we have been climbing? can't you have been climbing? can't they have been climbing?