用所给单词的适当形式填空.

1. We should give up those _______ (waste) habits in order to save our world.

2. The foreigners had an _______ (enjoy) time on the Great Wall yesterday.

3. I think __________(environment) education for kids is necessary.

4. Most students in our school often collect _______ (reuse) waste for recycling.

5. If we don't look after our earth well, the future will be _______ (hope).