It is generally true that the lower the stock market falls, ________ .

Because aluminum is lighter and cheaper ________, it is frequently used for high-tension power transmission.

Within an area of only 100 miles, Death Valley sinks to 282 feet below sea level while Mount Whitney ________ to a height of 14,494 feet.

A good teaching technique for ________ students active is group work.

Isaac Newton, ________, made his discoveries about gravity nearly 300 years ago.

George would certainly have attended the proceedings ________.

Ancient civilizations such as the Phoenicians and the Mesopotamians ________ goods rather than use money.

The television programs we allow ________ to watch influence their learning.

Helen Keller lost both her sight and hearing after a severe illness ________.

The most exact way known to science ________ the age of artifacts is based on the radioactivity of certain minerals.