上海高考英语选词填空专项练习

Section B

Directions: Complete the following passage by using the words in the box. Each word can only be used once. Note that there is one word more than you need.

Beyond two or three days, the world’s best weather forecasts are based on guesswork, and beyond six or seven they are worthless.

The Butterfly Effect is the reason. For small pieces of weather — and to a global forecaster, small can mean thunderstorms and snowstorms—any ___41___ fails rapidly. Errors and uncertainties ___42___, gathering upward through a chain of unstable features, from dust devils (尘旋风) and windstorms up to continent-size eddies (旋风) ___43___ satellites can see.

The modern weather models work with a network of points of the order of sixty miles apart, and even so, some ___44___ data has to be guessed, since ground stations and satellites cannot see everywhere. But suppose the earth could be covered with sensors spaced one foot apart, rising at one-foot ___45___ all the way to the top of the atmosphere. Suppose every sensor gives perfectly ___46___ readings of temperature, pressure, dampness, and any other quantity a meteorologist (气象工作者) would want. Exactly at noon a(n) ___47___ powerful computer takes all the data and ___48___ what will happen at each point at 12.01, then 12.02, then 12.03 …

The computer will still be unable to predict whether Princeton, New Jersey, will have sun or rain on a day one month away. At noon the spaces between the sensors will ___49___ alterations that the computer will not know about, tiny variations from the ___50___. By 12.01, those alterations will already have created small errors one foot away. Soon the errors will have multiplied to the ten-foot scale, and so on up to the size of the globe.

Keys:

41-45 KJIGH 46-50 AFDEC

Section B

Directions: Complete the following passage by using the words in the box. Each word can only be used once. Note that there is one word more than you need.

Rain forests, found in Earth’s temperate and tropical (热带的) zones, are some of the most biologically varied ecosystems on the planet. All rain forests share certain ___41___ features, including a closed canopy, thedensevegetation of thetop branches that forms a roof above the forest floor, a damp and warm climate, and ___42___ constant temperatures throughout the year. Most of the forest’s insect and animal life grows well in the canopy’s leafy and sunlit environment. The forest’s groundcover, by comparison, is small. Less than 2 percent of the sun’s li ght makes its way through the canopy and the darkness below. This darkness, along with the poor quality of the soils, ___43___ plant growth.

Rain forests are a(n) ___44___ part of Earth’s total ecology. Huge amounts of water are absorbed into tree roots and ___45___ into the atmosphere from the tree leaves through a process called transpiration(蒸发). Tree roots also fix the soil in place and slow the runoff of rains into rivers and oceans. Through the process of photosynthesis (光合作用), rain forests absorb more carbon dioxide and give off more oxygen than any other ecosystem.

The rain forests are ___46___ shrinking at a rapid rate as a result of the profitable ventures of farming, logging, and mining. When tropical rain forests are ___47___ in order to raise cattle and crops, the nutrient-poor soils are quickly