单项选择
2. jim has ___________ done his homework. have you finished yours __________? a. already, yet b. already, already c. yet, yet d. yet, already
a. already, yet already, 一般用在肯定句中,不用在否定句和疑问中,表示已经 yet, 一般用在否定句和疑问句中。 意思是 ---还
答:B, For a long time they walked without saying a word.Jim was the first to break ...详情>>
答:原因就在这: 圆的周长应该是2πR。这是数学知识。而为了方便把角度用实数来表示,人们引入了弧度制,即等于半径的弧长对应的圆心角是一弧度角。那么,一个圆周对应的是...详情>>