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

Have you ever had goldfish as pets? In fact, people in medieval Europe_____________that goldfish was a mythical creature.