Howdidpeopletellthetimebeforeclockswereinvented?Atfi...
問題詳情： Howdidpeopletellthetimebeforeclockswereinvented?Atfirst,theancientpeoplelookedupatthesunandcouldtellitwasthemiddleofthedaywhenthesunwasdirectlyoverheadinthesky.Theyalsoknewwhenitwasmorni...