1. If I were you, I would use energy efficient light bulbs.

2. He came up with a great idea for our enviromental project.

3. Because of being absent from the meeting, she didn't know the resolution.

4. If I had enough free time, I would take part in the volunteer program.

5. If we don't reduce our plastic waste, we'll threaten our own existence.

1.If  I were you,I would use energy efficeient light bulbs.(if 2)

2.He came up with a great idea for our enviromental project.(came up with:xuất hiện,nghĩ ra)

3.Beacuse of being absent from the meeting,she didn't know the resolution.(becasue of+N/V-ing)

4.If I have enough time,I will take part in volunteer program.(if 1)

5.If we don't reduce our plastic watse,we'll threaten our own existence.(if 1)