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