____, she led a life of complete seclusion.

It’s necessary ______ us to keep our pets clean everyday.

The ____of AIDS has led to an expansion in research seeking a cure.

California is a land of variety and contrast. Almost every type of physical land feature ， sort of arctic ice fields and tropical jungles can be found within its borders. Sharply contrasting types of land often lie very close to one another. People living in Bakersfield ， for instance，can visit the Pacific Ocean and the coastal plain ， the fertile San Joaquin Valley ， the arid Mojave Desert ， and the high Sierra Nevada， all within a radius of about 100 miles. In other areas it is possible to go snow skiing in the morning and surfing in the evening of the same day ， without having to travel long distance. Contrast abounds in California. The highest point in the United States (outside Alaska ) is in California ， and so is the lowest point (including Alaska )。 Mount Whitney ， 14，494 feet above sea level，is separated from Death Valley ， 282 feet below sea level，by a distance of only 100 miles. The two areas have a difference in altitude of almost three miles. California has deep ， clear mountain lakes like Lake Tahoe ， the deepest in the country， but it also has shallow， salty desert lakes. It has Lake Tulainyo ， 12，020 feet above sea level， and the lowest lake in the country ， the Salton Sea， 236 feet below sea level. Some of its lakes ， like Owens Lake in Death Valley ， are not lakes at all： they are dried up lake beds. In addition to mountains ，lakes， valleys，deserts， and plateaus，California has its Pacific coastline， stretching longer than the coastlines of Oregon and Washington combined.

1. Which of the following is the lowest point in the United States?

A. Lake Tulainyo B. Mojave desert C. Death Valley D. The Salton Sea

2. Where is the highest point in the United States located ?

A. Lake Tahoe.

B. Sierra Nevada. C. Mount Whitney.

D. Alaska.

3. How far away is Death Valley from Mount Whitney?

A. About 3 miles.

D. 14，494 feet.

4. Which of the following is NOT mentioned in the passage as being within a radius ofabout 100 miles of Bakersfield ?

A. The Pacific Ocean.

B. San Joaquin Valley.

C. Mojave Desert.

D. Oregon andWashington.

5. Which statement best demonstrates that California is a land of variety and contrast ?

A. The highest lake in California is Lake Tulainyo.

B. It is possible to go surfing and snow skiing in some parts of California without having totravel long distance.

C. Sierra Nevada， San Joaquin Valley， Mojave Desert and the Pacific Ocean all lie withina radius of about 100 miles.

D. Owens Lake ， in Death Valley ， is not really a lake at all.

HowI_____Icouldliveonthemoon.