1.How many pens are there on the desk?
2.Are there any ducks in the river?3.There is a book in a bag.（改成复数句）4.There is waiter waiting for you.(改为一般疑问句）5.There is (an apple) in his bag.(对打括号部分提问)3. There are many books in the bags.4. Is there waiter waiting for you?5. What is there in his bag?