the book are on the bookcase .改为否定句 the baseball is under th

the book are on the bookcase .改为否定句 the baseball is under the bed.改为一般疑问句

1.原句 ：The books are on (aren't) the bookcase .
否定句 ：The books are not (aren't) on the bookcase .
(我觉得你题目上的单词 book 应该是单词books ,因为你在后面用了are一词.而单词are是一个用于复数形式的单词）
2.原句 ：The baseball is under the bed.
一般疑问句 ：Is the baseball is under the bed .