I can't specifically tell what you learnt in Unit 5, but these are some actions you can take to preserve the environment in Spanish:
In this case, there are plenty of actions to take to preserve the environment. Since you have to write these sentences in Spanish, it is imortant that you pay attention to key words to write the sentences correctly.
You can think about what you would do to preserve the environment, write the sentences in English, and then try to translate the sentences in Spanish using those key words.
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