Since lightning was probably significant in the formation of life, understanding it might help us ________ life itself

Supersonic transport .......... the Concorde will probably be widely accepted as soon as problems of noise and atmospheric pollution are resolved.

A vacuum will neither conduct heat nor ..............

Your mistakes in composition are similar ............. his

A ............. is a person who searches for valuable minerals.

................ poetry is more enjoyable when it is read aloud.

One way to inform the public about factories that pollute the environment is through ............ programs on TV.

The practical and legal implications of euthanasia, the practice of causing the death of a person suffering from an incurable disease, are so controversial .......... it is illegal in most countries.

Without alphabetical order, dictionaries would be ............... to use.

In 1975, according to the national center for health statistics, the average life expectancy for people born during that year ............... 72.4 years

The exam results could .............. your career.

Often a team of engineers is ..............

Optical fibers ............. to deliver laser light.

John F. Kennedy was the youngest president of the United States and ........... to be assassinated.

Oscillatona, one of the few plants that can move about, ............ a wavy, gliding motion.

................. thought was given, but all was not approved.

In ancient times and throughout the middle ages, many people believed that the earth ........... motionless.

Goods for sale at ............... prices.

Three dangerous criminals escaped ................. prison yesterday.

If the oxygen supply in the atmosphere ......... replenished by plants, it would soon be exhausted.

The flag of the original colonies may or may not have been ............ by Betsy Ross during the revolution.

Nitrogen must be .......... with another element such as hydrogen or oxygen to be useful in agriculture or industry

Double-star orbit ..............

Civil engineers had better .............. to use steel supports in concrete structures built on unstable geophysical sites

Green and magneta are complementary colors located opposite each other on the color wheel, ................

Traditionally, the flag is .......... in the morning and taken down at night.

All the cereal grains ........... grow on the prairies and plains of the United States.

The corals can be divided into three groups, two of which ............. extinct

The extent to which an individual is a product of either heredity or environment ............ but several theories have been proposed

Jane Addams had already established full house in Chicago and ............ her work in the women's suffrage movement when she was awarded the Nobel prize for peace.

I need to earn ........... money, but then I lost my job.

Starfishes and sea urchins, members of the echinoderms or spiny skinned animals, are particularly ........... because of their unusual structures

All of them are freshmen, ............................ whom come from countryside.

I didn't enjoy this book on how to succeed in business. It wasn't very.................

I was shocked ........... the news of the crashed plane.

Because .............. food is as nutritious for a baby as its mother's milk, many women are returning to the practice of breast feeding.

Anyone reproducing copyrighted works without permission of the holders of the copyrights .............. breaking the law.

To relieve pain caused by severe burns, prevent infection, and treat for shock, ...............

Every country ........... a national flag

A .............. mountaineer reached the top of the Himalaya last week