Ifyoureadacloc的精選

問題詳情：短文填空。根據下面短文內容，在短文的空格處填上一個恰當的詞，使短文完整、通順。  Ifyoureadaclock,youcanknowthetimeofday.Buthowdidtheearlypeopleknowaboutthetime?  Wecannotseeorheartime.Weknowito...