Put the verbs in brackets in the correct forms to complete the sentences.
1. When I (to come) home, mother already (to cook) dinner.
2. Jane always (to help) her mother about the house. Today she (to help) her mother since morning.
3. Listen! The bird (to sing) a beautiful song.
4. What Terry (to do) when you (to meet) him?
5. How long they (to know) each other?
6. Why she (to come) home so late tomorrow?