用there be句型造句并变为否定,疑问,肯定句,并做肯否定回答.单复数句都要,

单数：肯定句：There is an apple on the desk.
否定：There isn`t an apple on the desk.
疑问：Is there an apple on the desk?
肯定回答：Yes,there is.
否定回答：No,there isn`t.
复数：肯定句：There are some apples on the desk.
否定：There aren`t any appples on the desk.
疑问：Are there any apples on the desk?
肯定回答：Yes,there are.
否定回答：No,there aren`t.