this is desk（一般问句,肯定回答）

this is desk（一般问句,肯定回答） is this a desk?（肯定回答） 怎么写? A,there is a computer on the desk改为否定句是什么?一般问句是什么?肯定,否定回答是什么 IS this teacher`s desk?怎么改为肯定回答 There is a pencil on the desk?（改为一般疑问句并作肯定回答） Jack is my classmate.（变成一般问句并肯定回答） This is a desk.(一般疑问句） This is our classroom.（一般疑问句,肯定回答） Whose book is this?（复数句） Is this your desk.(怎么回答） This is a teacher's desk(改为一般疑问句,并作否定回答.）求教 把That is a desk改为一般疑问句并作肯定回答,否定回答 there is a desk in my room 一般疑问句 否定回答和肯定回答