問題詳情

Questions 29-40The largest of the giant gas planets, Jupiter, with a volume 1,300 times greater thanEarth’s, contains more than twice the mass of all the other planets combined. It is thoughtto be a gaseous and fluid planet without solid surfaces, Had it been somewhat more massive,Jupiter might have attained internal temperatures as high as the ignition point for nuclear5)reactions, and it would have flamed as a star in its own right. Jupiter and the other giantplanets are of a low-density type quite distinct from the terrestrial planets: they arecomposed predominantly of such substances as hydrogen, helium, ammonia, and methane,unlike terrestrial planets. Much of Jupiter’s interior might be in the form of liquid, metallichydrogen, Normally, hydrogen is a gas, but under pressures of millions of kilograms per10)square centimeter, which exist in the deep interior of Jupiter, the hydrogen atoms mightlock together to form a liquid with the properties of a metal. Some scientists believe thatthe innermost core of Jupiter might be rocky, or metallic like the core of Earth.Jupiter rotates very fast, once every 9.8 hours. As a result, its clouds, which are composedlargely of frozen and liquid ammonia, have been whipped into alternating dark and bright15)bands that circle the planet at different speeds in different latitudes. Jupiter’s puzzlingGreat Red Spot changes size as it hovers in the Southern Hemisphere. Scientists speculateit might be a gigantic hurricane, which because of its large size (the Earth could easily fitinside it), lasts for hundreds of years.Jupiter gives off twice as much heat as it receives from the Sun. Perhaps this is primeval20)heat or beat generated by the continued gravitational contraction of the planet. Anotherstarlike characteristic of Jupiter is its sixteen natural satellites, which, like a miniature modelof the Solar System, decrease in density with distance—from rocky moons close to Jupiterto icy moons farther away. If Jupiter were about 70 times more massive, it would havebecome a star, Jupiter is the best-preserved sample of the early solar nebula, and with itssatellites, might contain the most important clues about the origin of the Solar System.
29. The word “attained” in line 4 is closest inmeaning to
(A) attempted
(B) changed
(C) lost
(D) reached

參考答案

答案：D
難度：非常簡單1
統計：A(0),B(0),C(0),D(4),E(0)

內容推薦

內容推薦