I can fence you can fence he can fence we can fence you can fence they can fence
V-ing form
I can be fencing you can be fencing he can be fencing we can be fencing you can be fencing they can be fencing
Perfect
I can have fenced you can have fenced he can have fenced we can have fenced you can have fenced they can have fenced
V-ing perfect
I can have been fencing you can have been fencing he can have been fencing we can have been fencing you can have been fencing they can have been fencing
Negation
Simple form
I can't fence you can't fence he can't fence we can't fence you can't fence they can't fence
V-ing form
I can't be fencing you can't be fencing he can't be fencing we can't be fencing you can't be fencing they can't be fencing
Perfect
I can't have fenced you can't have fenced he can't have fenced we can't have fenced you can't have fenced they can't have fenced
V-ing perfect
I can't have been fencing you can't have been fencing he can't have been fencing we can't have been fencing you can't have been fencing they can't have been fencing
Interrogative form
Simple form
can I fence? can you fence? can he fence? can we fence? can you fence? can they fence?
V-ing form
can I be fencing? can you be fencing? can he be fencing? can we be fencing? can you be fencing? can they be fencing?
Perfect
can I have fenced? can you have fenced? can he have fenced? can we have fenced? can you have fenced? can they have fenced?
V-ing perfect
can I have been fencing? can you have been fencing? can he have been fencing? can we have been fencing? can you have been fencing? can they have been fencing?
Interro-negative form
Simple form
can't I fence? can't you fence? can't he fence? can't we fence? can't you fence? can't they fence?
V-ing form
can't I be fencing? can't you be fencing? can't he be fencing? can't we be fencing? can't you be fencing? can't they be fencing?
Perfect
can't I have fenced? can't you have fenced? can't he have fenced? can't we have fenced? can't you have fenced? can't they have fenced?
V-ing perfect
can't I have been fencing? can't you have been fencing? can't he have been fencing? can't we have been fencing? can't you have been fencing? can't they have been fencing?