I can grab you can grab she can grab we can grab you can grab they can grab
V-ing form
I can be grabbing you can be grabbing she can be grabbing we can be grabbing you can be grabbing they can be grabbing
Perfect
I can have grabbed you can have grabbed she can have grabbed we can have grabbed you can have grabbed they can have grabbed
V-ing perfect
I can have been grabbing you can have been grabbing she can have been grabbing we can have been grabbing you can have been grabbing they can have been grabbing
Negation
Simple form
I cannot grab you cannot grab she cannot grab we cannot grab you cannot grab they cannot grab
V-ing form
I cannot be grabbing you cannot be grabbing she cannot be grabbing we cannot be grabbing you cannot be grabbing they cannot be grabbing
Perfect
I cannot have grabbed you cannot have grabbed she cannot have grabbed we cannot have grabbed you cannot have grabbed they cannot have grabbed
V-ing perfect
I cannot have been grabbing you cannot have been grabbing she cannot have been grabbing we cannot have been grabbing you cannot have been grabbing they cannot have been grabbing
Interrogative form
Simple form
can I grab? can you grab? can she grab? can we grab? can you grab? can they grab?
V-ing form
can I be grabbing? can you be grabbing? can she be grabbing? can we be grabbing? can you be grabbing? can they be grabbing?
Perfect
can I have grabbed? can you have grabbed? can she have grabbed? can we have grabbed? can you have grabbed? can they have grabbed?
V-ing perfect
can I have been grabbing? can you have been grabbing? can she have been grabbing? can we have been grabbing? can you have been grabbing? can they have been grabbing?
Interro-negative form
Simple form
can I not grab? can you not grab? can she not grab? can we not grab? can you not grab? can they not grab?
V-ing form
can I not be grabbing? can you not be grabbing? can she not be grabbing? can we not be grabbing? can you not be grabbing? can they not be grabbing?
Perfect
can I not have grabbed? can you not have grabbed? can she not have grabbed? can we not have grabbed? can you not have grabbed? can they not have grabbed?
V-ing perfect
can I not have been grabbing? can you not have been grabbing? can she not have been grabbing? can we not have been grabbing? can you not have been grabbing? can they not have been grabbing?