can ski
Regular verb: ski - skied- skied

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can ski
you can ski
she can ski
we can ski
you can ski
they can ski 	I can be skiing
you can be skiing
she can be skiing
we can be skiing
you can be skiing
they can be skiing	I can have skied
you can have skied
she can have skied
we can have skied
you can have skied
they can have skied	I can have been skiing
you can have been skiing
she can have been skiing
we can have been skiing
you can have been skiing
they can have been skiing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can't ski
you can't ski
she can't ski
we can't ski
you can't ski
they can't ski 	I can't be skiing
you can't be skiing
she can't be skiing
we can't be skiing
you can't be skiing
they can't be skiing	I can't have skied
you can't have skied
she can't have skied
we can't have skied
you can't have skied
they can't have skied	I can't have been skiing
you can't have been skiing
she can't have been skiing
we can't have been skiing
you can't have been skiing
they can't have been skiing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I ski?
can you ski?
can she ski?
can we ski?
can you ski?
can they ski? 	can I be skiing?
can you be skiing?
can she be skiing?
can we be skiing?
can you be skiing?
can they be skiing? 	can I have skied?
can you have skied?
can she have skied?
can we have skied?
can you have skied?
can they have skied? 	can I have been skiing?
can you have been skiing?
can she have been skiing?
can we have been skiing?
can you have been skiing?
can they have been skiing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can't I ski?
can't you ski?
can't she ski?
can't we ski?
can't you ski?
can't they ski? 	can't I be skiing?
can't you be skiing?
can't she be skiing?
can't we be skiing?
can't you be skiing?
can't they be skiing? 	can't I have skied?
can't you have skied?
can't she have skied?
can't we have skied?
can't you have skied?
can't they have skied? 	can't I have been skiing?
can't you have been skiing?
can't she have been skiing?
can't we have been skiing?
can't you have been skiing?
can't they have been skiing?