[单项选择]________into oceans and rivers is a serious form of pollution.
A. Pouring sewage
B. Emptying litter
C. Throwing garbage
D. Dumping sewage

[单项选择]________into oceans and rivers is a serious form of pollution.
A. Pouring sewage
B. Emptying litter
C. Throwing garbage
D. Dumping sewage

[单项选择]（）into oceans and rivers is a serious form of pollution.
A. Pouring sewage
B. Emptying litter
C. Throwing garbage
D. Dumping sewage

[单项选择]The least serious form of brain trauma, characterized by a brief loss of consciousness and period of confusion, is called
A. contusion.
B. concussion.
C. coup.
D. contrecoup.

[单项选择]We learn from the passage that the original form of Mr. Potato Head ______.
A. was very ugly and refused by customers
B. was designed during the World War Ⅱ era
C. was completely made of eatable potatoes
D. was made up of several separate parts

[单项选择]Court life was governed by the most precise form of ______.
A. oracle
B. moratorium
C. etiquette
D. neurosis

[单项选择]There is nothing serious ______ I had jumped out of the window when the bomb exploded.
A. as well as I am concerned
B. as long as I am concerned
C. as I am concerned
D. as far as I am concerned

[单项选择]Found in all oceans thevarious species of electric rays use the charge they can generate for both stunning prey or warding off predators.

[单项选择]

Passage Four
The atmosphere and oceans are not the only parts of the environment being damaged. Rain forests are being quickly destroyed as well, and their survival is questionable. E. O. Wilson, a biologist at Harvard, calls the depletion(枯竭、耗尽)of rain forest areas "the greatest extinction since the end of the age of dinosaurs(恐龙)".
Unlike some environmental issues, ram forest depletion has fortunately received significant public and media attention. Despite the opposition to the cutting down of rain forests, the problem continues. Every year, Brazil chops down on area of forest the size of the state of Nebraska. In addition to the Amazon’s rain forests, many other forests are being cut down as well. In Indonesia, Zaire, Papua New Guinea, Malaysia, Burme, the Philippines peru, Colombia, Bolivia, and Venezuela, rain forests that were once great have been lost.
According to some estimates, 50 million acres of rain forest are cu
A. The United Nations says about 50 million acres of rain forests are cut down every year.
B. Luckily people and mass media all paid special attention to the depletion of rain forests.
C. The author thought the oceans' survival is questionable.
D. People have stopped cutting down rain forests because of the opposition of most peopl

[单项选择]The passage asserts that one reason that oceans become enriched in oxygen-18 as ice sheets grow is because______.


A. water molecules containing oxygen-18 condense and fall as precipitation slightly sooner
B. the ratio of oxygen-18 to oxygen-16 in water vapor evaporated from oceans if different from that of these isotopes in seawater
C. growing ice sheets tend to lose their oxygen-18 as the temperature of the oceans near them gradually decreases
D. less water vapor evaporates from oceans during glacial periods and therefore less oxygen-18 is removed from the seawater

[单项选择]The world is （　） seven continents and four oceans.
A. made up of
B. made out of
C. made from
D. made in

[单项选择]What can we learn about rivers in Australia


A. Rivers run higher than usual.
B. Rivers have run out of water.
C. Rivers cause little damage.
D. Every year rivers overflow.