按要求改变下列句子。

1.Their dictionaries are on the desk.  (对画线部分提问)

_____ _____ their dictionaries?

2.There is a library behind the science lab.  (变成一般疑问句,并作肯定回答)

--- ______ _____ a library behind the science lab?  

--- Yes, _____ _____.

3.My book is behind the desk. (变成一般疑问句,并作否定回答)

-- _____ ______ book behind the desk?  

-- No, it _____.

4.They are not pencil- boxes.  (改为单数句)

It ____ _____ ____ pencil-box.

5.You and I are in the gym now. (用复数第一人称代替画线部分)

______ are in the park now.