I can grasp you can grasp he can grasp we can grasp you can grasp they can grasp
V-ing form
I can be grasping you can be grasping he can be grasping we can be grasping you can be grasping they can be grasping
Perfect
I can have grasped you can have grasped he can have grasped we can have grasped you can have grasped they can have grasped
V-ing perfect
I can have been grasping you can have been grasping he can have been grasping we can have been grasping you can have been grasping they can have been grasping
Negation
Simple form
I cannot grasp you cannot grasp he cannot grasp we cannot grasp you cannot grasp they cannot grasp
V-ing form
I cannot be grasping you cannot be grasping he cannot be grasping we cannot be grasping you cannot be grasping they cannot be grasping
Perfect
I cannot have grasped you cannot have grasped he cannot have grasped we cannot have grasped you cannot have grasped they cannot have grasped
V-ing perfect
I cannot have been grasping you cannot have been grasping he cannot have been grasping we cannot have been grasping you cannot have been grasping they cannot have been grasping
Interrogative form
Simple form
can I grasp? can you grasp? can he grasp? can we grasp? can you grasp? can they grasp?
V-ing form
can I be grasping? can you be grasping? can he be grasping? can we be grasping? can you be grasping? can they be grasping?
Perfect
can I have grasped? can you have grasped? can he have grasped? can we have grasped? can you have grasped? can they have grasped?
V-ing perfect
can I have been grasping? can you have been grasping? can he have been grasping? can we have been grasping? can you have been grasping? can they have been grasping?
Interro-negative form
Simple form
can I not grasp? can you not grasp? can he not grasp? can we not grasp? can you not grasp? can they not grasp?
V-ing form
can I not be grasping? can you not be grasping? can he not be grasping? can we not be grasping? can you not be grasping? can they not be grasping?
Perfect
can I not have grasped? can you not have grasped? can he not have grasped? can we not have grasped? can you not have grasped? can they not have grasped?
V-ing perfect
can I not have been grasping? can you not have been grasping? can he not have been grasping? can we not have been grasping? can you not have been grasping? can they not have been grasping?