Tự luận
Grammar
Make compound or complex sentences, using the prompts and the words in brackets.
1. students / keep / homes / schools / green / clean / contribute / Go Green / campaign (if)
2. burning / fossil fuels / emit / harmful gases / people / still / use / heating / cooking (but)
3. city buses / taxis / use / noise reduction devices / run / environmentally friendly / fuels (and)
4. many residents / coal fires / cooking / can / seriously / pollute / air / city (which)
5. they / use / corn / make / bio-fuels / may / lead / food shortages (which)