1. To stop riding in cars is hard. (改为同义句)
to stop riding in cars.
2. You shouldn't use paper napkins anymore. (改为祈使句)
use paper napkins anymore.
3. Don't turn on the water in the shower while you are washing your hair. (改为同义句)
the water in the shower while you are washing your hair.
4. Jessica used old clothes to make bags. (改为被动语态)
Old clothes to make bags by Jessica.
5. The old man recycled paper ten years ago. (改为现在完成时)
The old man paper for ten years.

1. It's hard
2. Don't
3. Turn off
4. were used
5. has recycled

May is National Bike Month. 1. ______ May is the beginning of summer and warm weather, so why not start right away and enjoy sunshine!
Ride out to protect the environment
2. ______ If you're biking to school, you are helping bring down the air pollution. 3. ______ And by getting your family to stop driving and start riding a bike, you can do your part in improving the air quality.
Burn calories
Cycling isn't just good for the environment and it's good for you too. 4. ______ It not only improves your physical health, but also your mental state of mind. It can really help you be a happier person.
Share the sunny summer
So get into that shed, and take out your old bike. Paint the bike blue. Put on a nice coat. Load up a number of songs. 5. ______ Be a fun-in-the-sun child! Enjoy yourself!

1. F
2. C
3. B
4. A
5. G