用现在进行时完成下列句子。
1. ________ your brother ________ (watch) TV now?
2. We ________________ (play) basketball now.
3. — What ________ she ________ (do)?
— She _________________ (ride) a bike.
4. Those boys ________ (play) football on the playground.
5. They ________ (talk) in English.
6. Those children ________________ (sing) in the classroom.
7. The naughty boy ________________ (swim) in the river.
8. ________ Mary ________ (play) the piano?