I can tug you can tug he can tug we can tug you can tug they can tug
V-ing form
I can be tugging you can be tugging he can be tugging we can be tugging you can be tugging they can be tugging
Perfect
I can have tugged you can have tugged he can have tugged we can have tugged you can have tugged they can have tugged
V-ing perfect
I can have been tugging you can have been tugging he can have been tugging we can have been tugging you can have been tugging they can have been tugging
Negation
Simple form
I can't tug you can't tug he can't tug we can't tug you can't tug they can't tug
V-ing form
I can't be tugging you can't be tugging he can't be tugging we can't be tugging you can't be tugging they can't be tugging
Perfect
I can't have tugged you can't have tugged he can't have tugged we can't have tugged you can't have tugged they can't have tugged
V-ing perfect
I can't have been tugging you can't have been tugging he can't have been tugging we can't have been tugging you can't have been tugging they can't have been tugging
Interrogative form
Simple form
can I tug? can you tug? can he tug? can we tug? can you tug? can they tug?
V-ing form
can I be tugging? can you be tugging? can he be tugging? can we be tugging? can you be tugging? can they be tugging?
Perfect
can I have tugged? can you have tugged? can he have tugged? can we have tugged? can you have tugged? can they have tugged?
V-ing perfect
can I have been tugging? can you have been tugging? can he have been tugging? can we have been tugging? can you have been tugging? can they have been tugging?
Interro-negative form
Simple form
can't I tug? can't you tug? can't he tug? can't we tug? can't you tug? can't they tug?
V-ing form
can't I be tugging? can't you be tugging? can't he be tugging? can't we be tugging? can't you be tugging? can't they be tugging?
Perfect
can't I have tugged? can't you have tugged? can't he have tugged? can't we have tugged? can't you have tugged? can't they have tugged?
V-ing perfect
can't I have been tugging? can't you have been tugging? can't he have been tugging? can't we have been tugging? can't you have been tugging? can't they have been tugging?