IV: Read the passage again and complete the sentences.
1. People in ---------------------------------------------------------areas have to gather wood to use as fuel.
2. Biogas is mainly used for -------------------------------------------------------------------------------------.
3. Biogas helps solve the problem of indoor ------------------------------------------------------------------
4. The use of renewable energy sources in developing countries is ----------------------------------------
5. In the future, the --------------------will be used as the main environmentally friendly energy sources.
IV: Read the passage again and complete the sentences.
rồi passage đâu :))?