Here are the prepositions of time to fill in the gaps in Jackie's timetable:

1) **On** Saturday he has karate class
2) **At** 9 a.m. In the afternoon, he has a martial arts class.
3) **At** 8 p.m. On Sunday morning, he has no plan. But he has a lot to do after lunch. He has a cycling competition. The competition is **at** 1:30.
4) **At** 4:00 p.m. Shortly after that, he has shuttlecock practice with his friends.

So the completed sentences would read:

1) On Saturday he has karate class
2) At 9 a.m. In the afternoon, he has a martial arts class.
3) At 8 p.m. On Sunday morning, he has no plan. But he has a lot to do after lunch. He has a cycling competition. The competition is at 1:30.
4) At 4:00 p.m. Shortly after that, he has shuttlecock practice with his friends.