Fill in the gaps with verbs in the proper progressive form .
i. Listen! The birds (sing)
2. We (drive) to the mountains this time next Saturday.
3. They (have) ... a picnic, when the rain started 4, I (read) a book last evening when I heard the fireworks.
5. Shhhh! Be quiet! My little sister (sleep)
6. They (not / do) ... their homework this afternoon: tomorrow's the weekend.
7. By this time tomorrow l (swim) ..in the central pool.
8. Mark and I (play) a computer game now.
9. I saw them. They (wait) ... in front of the shop.

1are singing2will be driving3were having4was reading5is sleeping6won't be doing7will have swum8are playing9were waiting10