Пре­об­ра­зуй­те, если это не­об­хо­ди­мо, слово CAN так, чтобы оно грам­ма­ти­че­ски со­от­вет­ство­ва­ло со­дер­жа­нию тек­ста.

Everybody knows that Christopher Columbus discovered America. Was he really the first to reach the continent? The great Norwegian explorer Thor Heyerdal believed that ancient people were able to build boats that ______ cross oceans.