10. Why did you take ________ son to school? Because _____________ bike broke down. A. your/he B. you/his C. your/his D. yo

10. Why did you take ________ son to school? Because _____________ bike broke down.
A. your/he B. you/his C. your/his D. your/him
11. Solar energy is a clean and ____________ energy source.
A. limited B. dangerous C. renewable D. non-renewable
12. ____________ fuels include oil, coal, and natural gas.
A. Ancient B. Cold C. Fossil D. Frozen
13. Nuclear power plants can ____________ electricity but they are harmful to environment.
A. drive B. do C. find D. generate
14. The sun and the wind are other ____________ sources of energy.
A. option B. choice C. changeable D. alternative
15. Solar power can be used to ____________ or cool our houses.
A. hotter B. heat C. hot D. heating
16. Coal is a ____________ source.
A. non-renewable B. abundant C. clean D. unlimited
17. In the future, the wind and the sun will be used as the main ____________ energy sources.
A. environmental friendly B. environmentally friendly
C. environmental friend D. environment friendly
18. Those non-renewable sources are going to ____________ soon.
A. exhausted B. lack C. use up D. run out
19. We should ____________ the lights before going to bed.
A. turn down B. turn up C. turn off D. turn on
20. Alternative energy sources are ____________, clean, safe, and cheap.
A. abundant B. exhausted C. limited D. expensive
21. People are ____________ the use of electricity to save energy.
A. reduce B. reducing C. to reduce D. reduces