I can sail you can sail he can sail we can sail you can sail they can sail
V-ing form
I can be sailing you can be sailing he can be sailing we can be sailing you can be sailing they can be sailing
Perfect
I can have sailed you can have sailed he can have sailed we can have sailed you can have sailed they can have sailed
V-ing perfect
I can have been sailing you can have been sailing he can have been sailing we can have been sailing you can have been sailing they can have been sailing
Negation
Simple form
I cannot sail you cannot sail he cannot sail we cannot sail you cannot sail they cannot sail
V-ing form
I cannot be sailing you cannot be sailing he cannot be sailing we cannot be sailing you cannot be sailing they cannot be sailing
Perfect
I cannot have sailed you cannot have sailed he cannot have sailed we cannot have sailed you cannot have sailed they cannot have sailed
V-ing perfect
I cannot have been sailing you cannot have been sailing he cannot have been sailing we cannot have been sailing you cannot have been sailing they cannot have been sailing
Interrogative form
Simple form
can I sail? can you sail? can he sail? can we sail? can you sail? can they sail?
V-ing form
can I be sailing? can you be sailing? can he be sailing? can we be sailing? can you be sailing? can they be sailing?
Perfect
can I have sailed? can you have sailed? can he have sailed? can we have sailed? can you have sailed? can they have sailed?
V-ing perfect
can I have been sailing? can you have been sailing? can he have been sailing? can we have been sailing? can you have been sailing? can they have been sailing?
Interro-negative form
Simple form
can I not sail? can you not sail? can he not sail? can we not sail? can you not sail? can they not sail?
V-ing form
can I not be sailing? can you not be sailing? can he not be sailing? can we not be sailing? can you not be sailing? can they not be sailing?
Perfect
can I not have sailed? can you not have sailed? can he not have sailed? can we not have sailed? can you not have sailed? can they not have sailed?
V-ing perfect
can I not have been sailing? can you not have been sailing? can he not have been sailing? can we not have been sailing? can you not have been sailing? can they not have been sailing?