1 . 单句改错
1. And hopes this can inspire more thinking on the topic!
2. When I studied chemistry in high school, I reconsidered my goal and decided to be a doctor. They were two reasons for the decision.
3. The instructor kept repeating the words, “Speed up!” “Slow down!” “Turning left!”
4. Making sure those kids and their families are safe, because living in a cave provides a different environment.
5. It was when I got back to my apartment where I first came across my new neighbour.
6. Not only do the use of plastic water bottles hurt your wallet, it also increases pollution and wastes energy and water.
7. At the top of the hill lie a cottage which has a wonderful view of the whole city.
8. How beautiful flowers they are selling in the shop!

2 . 单句改错
1. It was just then when I began to worry about my safety
2. In a word, success is important, and so does failure, because it's the mother of success.
3. My dear friends, don't afraid of problems, but take advantage of them to be the best of ourselves.
4. There has a big library in our school.
5. That's all. Thank you. Some questions？