1. If people (to work together) our planet (to be saved 2. If air (to be polluted) we (to breathe) toxic gases. 3. If you (to throw away) rubbish into the bin our streets (to be) cleaner. 4. We (to save) nature if we (to recycle) used materials. 5. Iffactories (togiveoff) toxicgasestheozonelayer (to be destroyed). 6. There (to be) smog in cities if factories and plants (to pollute) air. 7. If waste (to be dumped) in the oceans lots of fish, animals and plants (to die out). 8. If the global warming (to continue) the polar ice (to melt).