I can climb you can climb she can climb we can climb you can climb they can climb
V-ing form
I can be climbing you can be climbing she can be climbing we can be climbing you can be climbing they can be climbing
Perfect
I can have climbed you can have climbed she 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 she can have been climbing we can have been climbing you can have been climbing they can have been climbing
Negation
Simple form
I cannot climb you cannot climb she cannot climb we cannot climb you cannot climb they cannot climb
V-ing form
I cannot be climbing you cannot be climbing she cannot be climbing we cannot be climbing you cannot be climbing they cannot be climbing
Perfect
I cannot have climbed you cannot have climbed she cannot have climbed we cannot have climbed you cannot have climbed they cannot have climbed
V-ing perfect
I cannot have been climbing you cannot have been climbing she cannot have been climbing we cannot have been climbing you cannot have been climbing they cannot have been climbing
Interrogative form
Simple form
can I climb? can you climb? can she climb? can we climb? can you climb? can they climb?
V-ing form
can I be climbing? can you be climbing? can she be climbing? can we be climbing? can you be climbing? can they be climbing?
Perfect
can I have climbed? can you have climbed? can she 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 she have been climbing? can we have been climbing? can you have been climbing? can they have been climbing?
Interro-negative form
Simple form
can I not climb? can you not climb? can she not climb? can we not climb? can you not climb? can they not climb?
V-ing form
can I not be climbing? can you not be climbing? can she not be climbing? can we not be climbing? can you not be climbing? can they not be climbing?
Perfect
can I not have climbed? can you not have climbed? can she not have climbed? can we not have climbed? can you not have climbed? can they not have climbed?
V-ing perfect
can I not have been climbing? can you not have been climbing? can she not have been climbing? can we not have been climbing? can you not have been climbing? can they not have been climbing?