Решение задания :выделите сказуемое, определите его видо-временную форму и укажите инфинитив:1.W.When

1. When I entered the office, the secretary was typing some letters.
Entered (to enter)- Past Simple.
Was typing (to type)- Past Continuous.
2. What are you talking about?
Are talking (to talk)- Present Continuous.
3. Did you travel around Europe last year?
Did travel (to travel)- Past Simple.
4. Dont come at 6, I shall be doing my homework.
Dont come (to come)- Imperative mood, Present Simple. 
Shall be doing (to do)- Future Continuous.
5. Will you come to the party with me?
Will come (to come)- Future Simple.
6. Every day my aunt bakes a cake for lunch.
Bakes (to bake)- Present Simple.
7. Yesterday I came home late.
Came (to come)- Past Simple.
8. What were you doing yesterday all day?
Were doing (to do)- Past Continuous.
9. I shall not play the piano tomorrow.
Shall play (to play)- Future Simple.