Решение : выделите сказуемое, определите его видо-временную форму и укажите инфинитив: 1.w.when i entered the office,the secretary was typing some letters. 2.what are you talking about? 3.did you travel around europe lest year? 4.don't come at 6, i shall be doing my homework. 5.will you come to the party with me? 6.every day my aunt bakes a cake for lunch. 7.yesterday i came home late. 8.what were you doing yesterday all day? 9.i shalln't play the piano tomorrow.

1. entered - past simp - to enter, was typing - past cont - to type.
2. are talking - pres cont - to talk.
3. Did travel - past simp - to travel.
4. Don't come - pres simp - to come, shall be doing - fut cont - to do.
5. Will come - fut simp - to come.
6. bakes - pres simp - to bake.
7. came - past simp - to come.
8. were doing - past cont - to do.
9. shalln't play - fut simp - to play.