Choose the correct answer A, B, C, or D. 1. In the future, many cars will run ________ electricity, which doesn’t cause air p

Choose the correct answer A, B, C, or D.
1. In the future, many cars will run ________ electricity, which doesn’t cause air pollution.
A. in B. on C. by D. with
2. You should turn the tap ________ when you brush your teeth to save water.
A. up B. down C. on D. off
3. You should donate your old clothes, toys and furniture to people in ________.
A. order B. fact C. need D. case
4. ________ robots can help to teach children in the classroom, they will never replace teachers.
A. When B. Although C. Because D. If
5. There are lots of ________ problems nowadays, mainly because of pollution.
A. natural B. social C. practical D. environmental
6. To ________ waste we should avoid buying products with a lot of packaging.
A. recycle B. reuse C. reduce D. remake
7. ‘Will robots be more and more expensive?’ ‘_______ Prices will become cheaper over time.’
A. Not at all. B. Sure. C. Sounds great! D. I think so.
8. The Amazon River is ________ river in the world.
A. the wider B. wider than C. the widest D. widest