按要求改写下列句子，每空一词。
1. Open the door, please. (改为否定句)
___ _ open the door, please.
2. I can see a cup of coffee on the table. (对画线部分提问)
___ _ can you __ __ on the table?
3. There are thirty students on the playground. (对画线部分提问)
How ______ ______ are there on the playground?
4. There are some birds in the tree. (改为一般疑问句)
___ _ there birds in the tree?
5. They often play basketball on the playground.(对画线部分提问)
___ _ ______ they often __ __ basketball?