I can think you can think he can think we can think you can think they can think
V-ing form
I can be thinking you can be thinking he can be thinking we can be thinking you can be thinking they can be thinking
Perfect
I can have thought you can have thought he can have thought we can have thought you can have thought they can have thought
V-ing perfect
I can have been thinking you can have been thinking he can have been thinking we can have been thinking you can have been thinking they can have been thinking
Negation
Simple form
I cannot think you cannot think he cannot think we cannot think you cannot think they cannot think
V-ing form
I cannot be thinking you cannot be thinking he cannot be thinking we cannot be thinking you cannot be thinking they cannot be thinking
Perfect
I cannot have thought you cannot have thought he cannot have thought we cannot have thought you cannot have thought they cannot have thought
V-ing perfect
I cannot have been thinking you cannot have been thinking he cannot have been thinking we cannot have been thinking you cannot have been thinking they cannot have been thinking
Interrogative form
Simple form
can I think? can you think? can he think? can we think? can you think? can they think?
V-ing form
can I be thinking? can you be thinking? can he be thinking? can we be thinking? can you be thinking? can they be thinking?
Perfect
can I have thought? can you have thought? can he have thought? can we have thought? can you have thought? can they have thought?
V-ing perfect
can I have been thinking? can you have been thinking? can he have been thinking? can we have been thinking? can you have been thinking? can they have been thinking?
Interro-negative form
Simple form
can I not think? can you not think? can he not think? can we not think? can you not think? can they not think?
V-ing form
can I not be thinking? can you not be thinking? can he not be thinking? can we not be thinking? can you not be thinking? can they not be thinking?
Perfect
can I not have thought? can you not have thought? can he not have thought? can we not have thought? can you not have thought? can they not have thought?
V-ing perfect
can I not have been thinking? can you not have been thinking? can he not have been thinking? can we not have been thinking? can you not have been thinking? can they not have been thinking?