Are these your brothers 怎么改为单数形式?

Are these your Are these your pencils? Are these books ( )(your)? are these your parents are these your cousin Are these your trousers?Yes,these are, These pens are your.henna Are these your _____(letter) John,are these books----(your) Are these your T-shirt These are your new jeans. Are these your ___(watch)? these are (they)books.those are (your) Are these your pens?（同义句转换） Are these ------------ -------------- 改句子:--Are these your notebook?--Yes,these are. --Are these your notebooks? --Yes,these are. 改错 英语翻译Are these your apples?Are these apples____? Are they your books?还是Are these your books?为什么?