1. She ..is enjoying.. her holiday with her family (enjoy)
2. Listen! Someone ...is knocking.... at the door (knock)
3. Be quiet! We ..are studying... in the library (study)
4. Lan ....is doing..... her homework ( do)
5. My grandfather ..is reading.... newspaper (read)
6. They ..are watching.. TV at home (watch)
7. The boys ...are playing.. football in the yard (play)
II:
1. is
2. are
3. is
4. am
5. am
III
1. am reading
2. are not watching
3. Is Mary having
4. Are you listening
5. is Nga speaking
6. is playing