Solution:
- 1. A: Why are your clothes dirty? B: Because I have been working (work) in the garden all morning.
- 2. A: Why are you upset? B: Because I have lost (lose) my car keys.
- 3. A: Would you like some homemade cake? B: Yes, please. It smells (smell) delicious.
- 4. A: Are you busy? B: Yes. I have been working (work) on this project all day and I have not finished (still/not finish).
- 5. A: Who is using (use) my MP3 player? B: I have.
- 6. A: What's that noise? B: Jason is having (have) a birthday party.
- 7. A: What do people wear (people/wear) on Remembrance Day? B: A little red paper poppy.
- 8. A: Have you found (you/find) a dress for the prom night? B: Unfortunately, not yet.
Answer: 1. have been working, 2. have lost, 3. smells, 4. have been working, have not finished, 5. is using, 6. is having, 7. do people wear, 8. Have you found