1. Last year, we had a school festival in fall. I couldn't join the school festival because I was sick and absent from school.
2. Last year, we had a sports day. I couldn't join the sports day because I had to go abroad with my parents.
(Would you check any errors in the short pasages? Thank you.)
1. Last fall we had a school festival. . . .
2. O.K.
Both short passages appear to be grammatically correct. However, there are a few minor improvements that can be made for clarity and flow:
1. Last year, we had a school festival in the fall. Unfortunately, I couldn't participate because I was sick and absent from school.
2. Last year, we had a sports day. Regrettably, I couldn't attend the event because I had to accompany my parents on an overseas trip.