把下列各句改为被动语态

1. We clean our classroom every day.

    Our classroom ________ ________ every day.

2. They produce silk in Suzhou.

    Silk ________ ________ in Suzhou.

3. They speak English in class.

    English ________ ________ ________ ________ in class.

4. He teaches us ten words every class.

    Ten words ________ ________ to us ________ ________ every class.

5. We use keys for opening the door.

    Keys ________ ________ ________ opening the door.