1. The test was so long that we couldn't finish it in an hour.
-> Since the test was so long ,we couldn't finish it in an hour
2. Doing exercises regularly will make us healthier.
-> If we do exercises regularly, we will healthier
3. "Why don't you stop working and take a rest, Peter ?"
-> He suggested Peter that he should stop working and take a rest
5. Students achieve good results because of learning the lessons carefully.
-> Because students learn the lessons carefully, they achieve good results
6. We can't go fishing in this lake because the water is highly polluted.
-> Because of the highly polluted water, we can't go fishing in this lake