1. Sam is tired because he has been riding a bike for 2 hours and has ridden 3 miles.
2. Mary is tired because she has been doing shopping since morning and has bought a lot of food.
3. Bill is tired because he has been reading detective stories for four hours and has read 2 stories.
4.Sally is tired because she has been making pancakes since 10 o'clock and has made 50 big pancakes.
5. Roy is tired because he has been watching videos for three hours and has seen 2 films.
6. Jack is tired because he has been training since morning and has thrown the ball 100 metres.
7. Sarah is tired because she has been washing up for four hours and has broken a few plates.
8. The children are tired because they have been planting flowers since 12 o'clock and have planted a lot of primroses.