Are these ____ the twins'?---Yes,they are.A.key B.box C.keys D.boxs

Are these ____ the twins'?---Yes,they are.A.key B.box C.keys D.boxs
Are these ____ the twins'?---Yes,they are.A.key B.box C.keys D.boxs

Are these ____ the twins'?---Yes,they are.A.key B.box C.keys D.boxs
C
首先 are 所以要复数
但box的复数是boxes错
所以选keys

C.keys

答案选C
因为：A、B都是单数不考虑了。D选项拼写错误，应该是boxes.