更多"For the last hundred years the clim"的相关试题:
[单项选择]For the last hundred years the climate has been growing much warmer. This has had a number of different effects. Since the beginning of the 20th century, glaciers (冰河) have been melting very rapidly. For example, the Muir Glacier in. Alaska has retreated 2 miles in 10 years. Secondly, rising temperatures have been causing the snowline to retreat on mountains all over the world. In Peru, for example, it has risen as much as 2,700 feet in 60 years.
As a result of this, vegetation has also been changing. In Canada, the agricultural crop line has shifted 50 to 100 miles northward. In the same way cool-climate trees like birches and spruce have been dying over large areas of Eastern Canada. In Sweden the tree line has moved up the mountains by as much as 65 feet since 1930.
According to the passage, the Muir Glacier has retreated because ______.
A. glaciers have been melting very gradually
B. the climate has been growing much warmer
C. the snowline has retreated on mountains
D. vegetation has been changing
[单项选择]During the last few years, it has been realized that maintenance of programs is more expensive than development, so reading of programs by humans is as important as (67) them.
A. editing
B. writed
C. written
D. writing
[单项选择]Over the last 40 years there has been a great increase not only in the number of agricultural pesticides in use but also in the care and sophistication with which they are used by farmers. Nevertheless, the proportion of agricultural crops lost to certain pests worldwide has increased over the same period, even when the pests concerned have not developed resistance to existing pesticides.
Which of the following, if true, best explains how improvements in pesticide use have been accompanied by greater losses to certain pests
A. Some dangerous but relatively ineffective pesticides common 40 years ago are no longer in widespread use.
B. As pesticides have become increasingly pest-specific, controlling certain pests with pesticides has turned out to cost more in many cases than the value of crop losses caused by those pests.
C. Because today’s pesticides typically have more specific application conditions than did pesticides in use 40 years ago, today’s farmers observe their fields more closely than did farmers 40 years ago.
D. Certain pest-control methods that some farmers use today do not involve the use of chemical pesticides but are just as effective in eliminating insect pests as those that do.
E. (E) Forty years ago, much less was known about the effects of pesticides on humans and other mammalian species than is now known.
[填空题]During the last few years, there has been an{{U}} (36) {{/U}}increase in the number of shops, stores and supermarkets which provide{{U}} (37) {{/U}}for self-service. Their general purpose is to provide goods of every{{U}} (38) {{/U}}attractively and cleanly and in perfect condition, so that the customer can serve herself, and then pay for the goods with the least{{U}} (39) {{/U}}.
The organizers of a self-service store have their difficulties. They must display a great number of goods in a{{U}} (40) {{/U}}space without covering up anything. They must deal with{{U}} (41) {{/U}}foodstuffs requiring different ranges of temperature; and they must arrange a{{U}} (42) {{/U}}flow of customers past the cash registers without{{U}} (43) {{/U}}the operators.
{{U}} (44) {{/U}}, rotating circular shelves, islands of display stands, racks for tubed foods, and multi-tiered mobile stalls.
{{U}} (45) {{/U}}These are at zero Fahrenheit for frozen food, 28-32 degrees fo