I can obtain you can obtain he can obtain we can obtain you can obtain they can obtain
V-ing form
I can be obtaining you can be obtaining he can be obtaining we can be obtaining you can be obtaining they can be obtaining
Perfect
I can have obtained you can have obtained he can have obtained we can have obtained you can have obtained they can have obtained
V-ing perfect
I can have been obtaining you can have been obtaining he can have been obtaining we can have been obtaining you can have been obtaining they can have been obtaining
Negation
Simple form
I cannot obtain you cannot obtain he cannot obtain we cannot obtain you cannot obtain they cannot obtain
V-ing form
I cannot be obtaining you cannot be obtaining he cannot be obtaining we cannot be obtaining you cannot be obtaining they cannot be obtaining
Perfect
I cannot have obtained you cannot have obtained he cannot have obtained we cannot have obtained you cannot have obtained they cannot have obtained
V-ing perfect
I cannot have been obtaining you cannot have been obtaining he cannot have been obtaining we cannot have been obtaining you cannot have been obtaining they cannot have been obtaining
Interrogative form
Simple form
can I obtain? can you obtain? can he obtain? can we obtain? can you obtain? can they obtain?
V-ing form
can I be obtaining? can you be obtaining? can he be obtaining? can we be obtaining? can you be obtaining? can they be obtaining?
Perfect
can I have obtained? can you have obtained? can he have obtained? can we have obtained? can you have obtained? can they have obtained?
V-ing perfect
can I have been obtaining? can you have been obtaining? can he have been obtaining? can we have been obtaining? can you have been obtaining? can they have been obtaining?
Interro-negative form
Simple form
can I not obtain? can you not obtain? can he not obtain? can we not obtain? can you not obtain? can they not obtain?
V-ing form
can I not be obtaining? can you not be obtaining? can he not be obtaining? can we not be obtaining? can you not be obtaining? can they not be obtaining?
Perfect
can I not have obtained? can you not have obtained? can he not have obtained? can we not have obtained? can you not have obtained? can they not have obtained?
V-ing perfect
can I not have been obtaining? can you not have been obtaining? can he not have been obtaining? can we not have been obtaining? can you not have been obtaining? can they not have been obtaining?