1. Everyone _________ __________ __________(应当) keep our environment clean.
2. People _________ _________ _________ (从……中产生电) the sun.
3. His main job is to _________ ________ (宣传) about the film.
4. Some plants are ________ _______ _______ (处于危险)disappearing.
5. It is too noisy last night. I couldn’t _________ ________ ________(设法睡觉)well. |