I can slip you can slip he can slip we can slip you can slip they can slip
V-ing form
I can be slipping you can be slipping he can be slipping we can be slipping you can be slipping they can be slipping
Perfect
I can have slipped you can have slipped he can have slipped we can have slipped you can have slipped they can have slipped
V-ing perfect
I can have been slipping you can have been slipping he can have been slipping we can have been slipping you can have been slipping they can have been slipping
Negation
Simple form
I cannot slip you cannot slip he cannot slip we cannot slip you cannot slip they cannot slip
V-ing form
I cannot be slipping you cannot be slipping he cannot be slipping we cannot be slipping you cannot be slipping they cannot be slipping
Perfect
I cannot have slipped you cannot have slipped he cannot have slipped we cannot have slipped you cannot have slipped they cannot have slipped
V-ing perfect
I cannot have been slipping you cannot have been slipping he cannot have been slipping we cannot have been slipping you cannot have been slipping they cannot have been slipping
Interrogative form
Simple form
can I slip? can you slip? can he slip? can we slip? can you slip? can they slip?
V-ing form
can I be slipping? can you be slipping? can he be slipping? can we be slipping? can you be slipping? can they be slipping?
Perfect
can I have slipped? can you have slipped? can he have slipped? can we have slipped? can you have slipped? can they have slipped?
V-ing perfect
can I have been slipping? can you have been slipping? can he have been slipping? can we have been slipping? can you have been slipping? can they have been slipping?
Interro-negative form
Simple form
can I not slip? can you not slip? can he not slip? can we not slip? can you not slip? can they not slip?
V-ing form
can I not be slipping? can you not be slipping? can he not be slipping? can we not be slipping? can you not be slipping? can they not be slipping?
Perfect
can I not have slipped? can you not have slipped? can he not have slipped? can we not have slipped? can you not have slipped? can they not have slipped?
V-ing perfect
can I not have been slipping? can you not have been slipping? can he not have been slipping? can we not have been slipping? can you not have been slipping? can they not have been slipping?