I can squint you can squint he can squint we can squint you can squint they can squint
V-ing form
I can be squinting you can be squinting he can be squinting we can be squinting you can be squinting they can be squinting
Perfect
I can have squinted you can have squinted he can have squinted we can have squinted you can have squinted they can have squinted
V-ing perfect
I can have been squinting you can have been squinting he can have been squinting we can have been squinting you can have been squinting they can have been squinting
Negation
Simple form
I cannot squint you cannot squint he cannot squint we cannot squint you cannot squint they cannot squint
V-ing form
I cannot be squinting you cannot be squinting he cannot be squinting we cannot be squinting you cannot be squinting they cannot be squinting
Perfect
I cannot have squinted you cannot have squinted he cannot have squinted we cannot have squinted you cannot have squinted they cannot have squinted
V-ing perfect
I cannot have been squinting you cannot have been squinting he cannot have been squinting we cannot have been squinting you cannot have been squinting they cannot have been squinting
Interrogative form
Simple form
can I squint? can you squint? can he squint? can we squint? can you squint? can they squint?
V-ing form
can I be squinting? can you be squinting? can he be squinting? can we be squinting? can you be squinting? can they be squinting?
Perfect
can I have squinted? can you have squinted? can he have squinted? can we have squinted? can you have squinted? can they have squinted?
V-ing perfect
can I have been squinting? can you have been squinting? can he have been squinting? can we have been squinting? can you have been squinting? can they have been squinting?
Interro-negative form
Simple form
can I not squint? can you not squint? can he not squint? can we not squint? can you not squint? can they not squint?
V-ing form
can I not be squinting? can you not be squinting? can he not be squinting? can we not be squinting? can you not be squinting? can they not be squinting?
Perfect
can I not have squinted? can you not have squinted? can he not have squinted? can we not have squinted? can you not have squinted? can they not have squinted?
V-ing perfect
can I not have been squinting? can you not have been squinting? can he not have been squinting? can we not have been squinting? can you not have been squinting? can they not have been squinting?