1. It's an English car. (改为复数形式)
   _____ English _____.
2. They are my boxes. ( 改为否定句)
    _____ _____ boxes.
3. These are rulers. (改为单数)
    This _____ _____ ruler.
4. We're in Class 4. (对划线部分提问)
   _____ class are _____ in?
5. Helen is thirteen. (对划线部分提问)
   _____ _____ is Helen?