His son's ....... has not improved much.

A. behave B. behaviour C. behavourist D. behavourism

Everyone has a number of ........, but no one has many true friends.

A. acquaint B. acquaintances C. acquainting D. acquainters

Why don't you call the ........ if the lights don't work?

A. electricity B. electric C. electrician D. electrics

The cost of the ..... must be paid by the buyer.

A. carry B. carrying C. carried D. carriage

The earthquake caused terrible .......

A. destroying B. destroyed C. destruction D. destroys

Sometimes I have some .... which can't be explained

A. fell B. felling C. feel D. feelings

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