Birds not only bring song, color, and activity to a garden ---are vitally needed by plants.

In a retail store, consumers ----the merchandise and compare brands.

As people get older, they usually become ------by ambition and more concerned with the value of their efforts.

In 1609 Galileo 'constructed' the first telescope, 'whom' he used to 'discover' the four largest 'satellites'...

Many employers are unable to express any opinion about 'which' local schools prepare 'they' students best of a...

If one lives a 'disorganized', 'pollution', crime-ridden world, 'one's' energies will be 'directed' at simple...

Silver, one of the first 'metal' used by 'humans' is an 'excellent' conductor of heat and 'electricity'.