Burning coal is an ..... way to heat the house. Gas is much cheaper.

A. economy B. economic C. uneconomical D. B&C

...... is now a serious problem in many countries.

A. Forest B. Forestry C. Deforestation D. Forestall

These ..... will conserve the earth's resources. (INNOVATE)

A. innovate B. innovation C. innovations D. innovative

My brother can repair electric .......... very well.

A. apply B. applicator C. application D. appliances

In the future, many buildings will be ....... by solar energy.

A. hot B. hoter C. hottest D. hotter

Environmental ....... is everybody's responsibility.

A. protect B. protection C. destruction D. damage

He decided, very ........., not to drive when he was so tired

A. sense B. sensitively C. sensibly D. sensible

We’ll live a happier and ...... life if we keep our environment clean.

A. health B. healthy C. unhealthy D. healthier

Don't eat those vegetables. They're ............

A. poison B. poisoning C. poisoned D. poisonous

You should write a letter of ..... to that institute.

A. inquire B. inquiry C. inquisition D. inquisitor