Fill in the Blanks Can, could, and be able to Online version With this test you can see if you understand the difference between can, could, and be able to. Let's see how far you got! by Nadia Gerritsen 1 could be was could to able able can to could James Cook sail very well , because he had been in the navy . Unlike other world explorers , Cook cross the Antarctic circle . Although he was a very successful explorer , he would never return to England . His misfortune began when an encounter with the native people of Hawaii did not go too well . Cook suggested that they take the Hawaiian chief captive to punish them . Unfortunately , Cook and his man not fight the natives and Cook was killed . This I tell you about James Cook and I will tell you more about Captain Cook once I have read his journal .