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Since life began eons ago, thousands of creatures have come and gone. Some, such as the dinosaurs, became extinct due to naturally changing ecologic conditions. More recent threats to life forms are humans and their activities. Man has drained marshes, burned prairies, dammed and diverted rivers. Some of the more recent casualties of man’s expansion have been the dodo, great auk, passenger pigeon, Irish elk, and Steller’s sea cow. Sadly, we can no longer attribute the increasing decline in our wild animals and plant species to "natural" processes. Many species are dying out because of exploitation, habitat alteration or destruction, pollution, or the introduction of new species of plants and animals to an area. As mandated by Congress, protecting endangered species, and restoring them to the point where their existence is no longer jeopa A. Glacial encroachment B. Hurricanes C. Dammed rivers D. Snowstorms [单项选择]
The development of toothpaste began as long ago as 3000/5000 BC in the ancient countries of China and India. According to Chinese history, Huang-Ti claimed different types of pain felt in the mouth could be cured by sticking gold and silver needles into different parts of the jaw and gum. h was theories such as these that led to the development of dental cream. During the years 3000/5000 BC, Egyptians made toothpaste using a recipe of powdered ashes of hooves of oxen, myrrh, powdered and burned eggshells and pumice. It is assumed that the ancient Egyptians used their fingers to rub the mixture onto teeth. [填空题]He began to study English six years ago.
He has studied English ______. [填空题]He began to study English six years ago.
He has studied English ______.
[单项选择]Since I began to work here three years ago, this factory ______ in size.
A. had doubled B. has doubled C. doubled [单项选择]Years ago, consumers in Finland began paying an energy tax in the form of two Finland pennies for each unit of energy consumed that came from nonrenewable sources. Following the introduction of this energy tax, there was a steady reduction in the total yearly consumption of energy from nonrenewable sources.
If the statements in the passage are true, then which of the following must on the basis of them be true A. There was a steady decline in the yearly revenues generated by the energy tax in Finland. B. There was a steady decline in the total amount of energy consumed each year in Finland. C. There was a steady increase in the use of renewable energy sources in Finland. D. The revenues generated by the energy tax were used to promote the use of energy from renewable sources. E. (E) The use of renewable energy sources in Finland greatly increased relative to the use of nonrenewable energy sources. [单项选择]About one million years ago, the Ice Age began. The Ice Age was a long period of time in which four great glaciers pushed southward to cover almost all the upper half of North America, and then melted away. Each glacier was a thick sheet of ice and snow that spread out from a centre near what is now Hudson Bay in Canada. The winters were long, and the cool summers were too short to melt much of the ice and snow. The ever-growing sheet built up to a thickness of two miles at its centre.
As all glaciers do, these great glaciers slid. They pushed down giant trees in their paths and scraped the earth bare of soil. Many animals moved farther south to escape. Others stayed and were destroyed. When winters of little snow came, the summer sun cut into the edges of the ice sheets. As the glaciers melted, rocks, soil and other things that had mixed with the ice and snow were left. New hills, lakes and rivers were formed. The last of the great glaciers began its melting about 11,00 A. the Ice Age was a long period of time B. great glaciers covered North America many years ago C. changes in climate helped to melt the glaciers D. how glaciers changed North America [单项选择]Hundreds of years ago, life was much harder than it is today. People didn’t have modern machines. There was no modern medicine, (41) .
Life today has brought new (42) . The biggest one is pollution. (43) pollution has made our rivers and lakes dirty. It kills our fish and pollutes our drinking water. Noise pollution makes us talk louder and become angry (44) easily. Air pollution is the most serious kind of pollution. That’s bad to all (45) things in the world. Cars, planes and factories all pollute our air every day. (46) the polluted air is so thick that it is like a quilt(被子) over a city. This kind of quilt is called smog(烟雾). Many countries are making rules to (47) pollution. Factories must now clean their water before it is thrown away. They mustn’t blow dirty into the air. We need to do many (48) things. We can put waste things in the dustbin and not throw it on the ground. We can go to work 我来回答: 提交
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