I can crawl you can crawl he can crawl we can crawl you can crawl they can crawl
V-ing form
I can be crawling you can be crawling he can be crawling we can be crawling you can be crawling they can be crawling
Perfect
I can have crawled you can have crawled he can have crawled we can have crawled you can have crawled they can have crawled
V-ing perfect
I can have been crawling you can have been crawling he can have been crawling we can have been crawling you can have been crawling they can have been crawling
Negation
Simple form
I cannot crawl you cannot crawl he cannot crawl we cannot crawl you cannot crawl they cannot crawl
V-ing form
I cannot be crawling you cannot be crawling he cannot be crawling we cannot be crawling you cannot be crawling they cannot be crawling
Perfect
I cannot have crawled you cannot have crawled he cannot have crawled we cannot have crawled you cannot have crawled they cannot have crawled
V-ing perfect
I cannot have been crawling you cannot have been crawling he cannot have been crawling we cannot have been crawling you cannot have been crawling they cannot have been crawling
Interrogative form
Simple form
can I crawl? can you crawl? can he crawl? can we crawl? can you crawl? can they crawl?
V-ing form
can I be crawling? can you be crawling? can he be crawling? can we be crawling? can you be crawling? can they be crawling?
Perfect
can I have crawled? can you have crawled? can he have crawled? can we have crawled? can you have crawled? can they have crawled?
V-ing perfect
can I have been crawling? can you have been crawling? can he have been crawling? can we have been crawling? can you have been crawling? can they have been crawling?
Interro-negative form
Simple form
can I not crawl? can you not crawl? can he not crawl? can we not crawl? can you not crawl? can they not crawl?
V-ing form
can I not be crawling? can you not be crawling? can he not be crawling? can we not be crawling? can you not be crawling? can they not be crawling?
Perfect
can I not have crawled? can you not have crawled? can he not have crawled? can we not have crawled? can you not have crawled? can they not have crawled?
V-ing perfect
can I not have been crawling? can you not have been crawling? can he not have been crawling? can we not have been crawling? can you not have been crawling? can they not have been crawling?