句型转换。按要求改写下列句子，每空一词。
（1）There is a book on the desk. （改为一般疑问句）
              a book on the desk?
（2）There are some cakes in the fridge. （改为否定句）
There      cakes in the fridge.
（3）There is a girl under the tree. （就划线部分提问）
______ ______ _______ ________ there under the tree?
（4）many, books, the, how, on, desk, there, are（?）（连词成句）
                                                      .