this is my book.写出下列句子的复数形式

this is my book。- These are my/our books。
Is that his uncle - Are those his/their uncles
Is she your friend?- Are they your friends
yes,it is。- Yes,they are。
this is my pencil case。- These are my/our pencil cases。
不明白的再问哟,请及时采纳,多谢!
再问： O(∩_∩)O谢谢 还有道题 连词成句(注意句后的标点符号) 1。sister,this,your,is_________________? 2。is,not,your eraser,that_______________。 3。friends,his,are,those_______________? 4。are,brothers,my,these_____________。 谢谢
再答： 1。 Is this your sister ? 2。 That is not your eraser。 3。 Are those his friends ? 4。 These are my brothers。