Sentence 5 talks about looking for alternate energy sources but doesn't specifically mention solar energy so it is wrong. Sentence 10 says that solar energy is a "significant development" but it doesn't provide specific evidence so it is also not correct. Sentence 6 is the best answer - it shows that it is already being used and it has the potential to be used even more.
It took place in the 13th century
Answer:
Hope this helps!!!
Explanation:
I bolded what I renewed/answer!
1. We (knew) each other since we were at school.
2. They (played) tennis every Sunday for years.
3. I (did not play) tennis.
4. You don't understand because you (did not listen).
5. How long have you been learning English? (Complete sentence change!)
6. You read the book yet?
7. I ate dinner, so let's go out.
8. I read the book you recommended but I'm not finished.
9. She finished her work already.
