I can solve you can solve he can solve we can solve you can solve they can solve
V-ing form
I can be solving you can be solving he can be solving we can be solving you can be solving they can be solving
Perfect
I can have solved you can have solved he can have solved we can have solved you can have solved they can have solved
V-ing perfect
I can have been solving you can have been solving he can have been solving we can have been solving you can have been solving they can have been solving
Negation
Simple form
I cannot solve you cannot solve he cannot solve we cannot solve you cannot solve they cannot solve
V-ing form
I cannot be solving you cannot be solving he cannot be solving we cannot be solving you cannot be solving they cannot be solving
Perfect
I cannot have solved you cannot have solved he cannot have solved we cannot have solved you cannot have solved they cannot have solved
V-ing perfect
I cannot have been solving you cannot have been solving he cannot have been solving we cannot have been solving you cannot have been solving they cannot have been solving
Interrogative form
Simple form
can I solve? can you solve? can he solve? can we solve? can you solve? can they solve?
V-ing form
can I be solving? can you be solving? can he be solving? can we be solving? can you be solving? can they be solving?
Perfect
can I have solved? can you have solved? can he have solved? can we have solved? can you have solved? can they have solved?
V-ing perfect
can I have been solving? can you have been solving? can he have been solving? can we have been solving? can you have been solving? can they have been solving?
Interro-negative form
Simple form
can I not solve? can you not solve? can he not solve? can we not solve? can you not solve? can they not solve?
V-ing form
can I not be solving? can you not be solving? can he not be solving? can we not be solving? can you not be solving? can they not be solving?
Perfect
can I not have solved? can you not have solved? can he not have solved? can we not have solved? can you not have solved? can they not have solved?
V-ing perfect
can I not have been solving? can you not have been solving? can he not have been solving? can we not have been solving? can you not have been solving? can they not have been solving?