1. If/ we/ cycle/ school/ every day/ we/ keep/ air/ clean and fresh.
If we cycle to school everyday, we will keep  air clean and fresh
2. If / you / often / do / exercise / feel / healthier
If you often do exercise, you will feel healthier
3. If/ you/ see/ used bottle/ road, what/ you/ do?
If you see used bottle, what  will you do?
4. If He/ throw / the rubbish, it / pollute /the environment.
If he throws the rubbish, it will pollute the environment
5. If / Nam / not / do / English exercises, he /get / poor / marks / school.
If Nam doesn't do English exercises, he will get poor marks at school