Ex.3
1. A: The journalist has written three articles about the hoax since last week.
B: The journalist wrote several articles on hoax stories last year.
2. A: My friend went to a computer workshop yesterday.
B: My friend has gone to a few computer workshops.
3. A: We haven't eaten a lot of food today so we're hungry now.
B: We didn't eat at the party last Saturday. We were busy dancing!
4. A: Kelvin participated in research and then the university paid him some money.
B: Kelvin has participated in many research projects already.
5. A: Have you finished your work yet?
B: Did you finish your work last week?
