单选题T.S.Elot, (who) a poet, playwright, (literary) critic, and editor, was (a leader) of the Modemist (movement) in poetry.

单选题Because its pitch cannot easily be altered, the oboe serves as the standard which by the symphony orchestra is tuned.

单选题1 The dominant feature on the map of Canada is the two-million-square-mile mass of ancient rock known as the Canadian Shield. The shield sweeps in a great arc around Hudson Bay from far northwest to far northeast, touching the Great Lakes on the south and extending eastward deep into Quebec. The rock of the shield consists mainly of granite and gneiss formed nearly four billion years ago. During the ice ages, huge glaciers advanced and retreated over the region, scouring the surface, removing most of the existing soil, and hollowing out countless lakes. 2 Clay soils exist in a few areas on the shield's southern edge, but attempts to bring them into agricultural use have been largely unsuccessful. However, the region's mineral wealth has sustained both temporary and permanent settlements during the past century, and more recently, some of its vast potential for hydroelectric power has been tapped.

单选题What is the role of pheromones ill the mass migrations of ants?

单选题Like Jupiter, Saturn is a large ,gaseous planet composed......of hydrogen and helium. (a)it is mostly (b)mostly (c)almost (d)both are almost

单选题The input of solar energy supplies 99 percent of the energy needed to heat the earth and all buildings on it. How is this possible? Most people think of solar energy in terms of direct heat from the sun. However, broadly defined, solar energy includes direct energy from the sun as well as a number of indirect forms of energy produced by this direct input. Major indirect forms of solar energy include wind, hydropower, and biomass--solar energy converted to chemical energy in trees, plants, and other organic matter. 3. It can be inferred from the passage that the author most likely believes which of the following about solar energy?

单选题Rain is slight acidic even in unpolluted air, because carbon dioxide in the atmosphere and other natural acid-forming gases dissolve in thewater.

单选题The midge ______ to any of several species of small flies, refers to a mosquito-like insect with slender wings and body, long legs, and antennae.

单选题If there is too much pituitary hormone of too few insulin, the amount of sugar in the blood rises abnormally, producing a condition called. Hyperglycemia.

单选题All of the following terms art defined in the passage EXCEPT

单选题The shell (of) the abalone, a marine snail, (is especially suited) by its hardness and (various) of colors (for) the manufacture of jewelry.

单选题According to the passage, when did the domestication of plants begin in North America?

单选题........ including climate, mineral content, and the permanency of surface water, wetlands may be mossy ,grassy, scrubby, or wooded. (a)Depending on many factors (b)Many factors depending on (c)Factors depending on many (d)On many factors depending

单选题The camera obscura, a lensless precursor of the photographic camera, (consists of) a (darkened) chamber, with light (pass) into it (through) a single tiny hole.

单选题For a seagoing, cargo-carrying sailing vessels, the clipper ship was remarkably fast.

单选题The word "attained" in line 24 is closest in meaning to

单选题The color and pageantry, keen rivalry, and high level of competition both contribute to {{/U}}the great worldwide interest in the Olympic Games.

单选题Until the twentieth century, pendulum clocks were calibrated against the rotation of earth by taking astronomically measurements.

单选题_____ the hamster’s basic diet is vegetarian, some hamsters also eat insects.