从括号中选出一个填空。

1. How ______ you?  (am, is ,are)

2. What ______ this in English? (am, is ,are)

3. What color is the pen? It ______ red. (am, is ,are)

4. What's this? It's ______ orange. (a, an )

5. What's this? It's ______jacket. (a, an )

6. It's ______ English book. (a, an )