托福词汇模拟练习题精选试题(五)

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　　401. At the heart of a comer's coma lies a nucleus of solid material, typically no more than 10 kilometers across.

　　The word "heart" is closest in meaning to which of following?

　　(A) center

　　(B) edge

　　(C) tail

　　(D) beginning

　　402. The most graphic proof that the grand spectacle of a comet develops from a relatively small and inconspicuous chunk of ice and dust was the close-up image obtained in 1986 by the European Giotto probe of the nucleus of Halley's Comet.

　　The word "graphic" is closest in meaning to which of following?

　　(A) mathematical

　　(B) popular

　　(C) unusual

　　(D) vivid

　　403. As a comet's orbit brings it closer to the Sun, first the coma grows, then two distinct tails usually form.

　　The word "distinct" is closest in meaning to which of following?

　　(A) visible

　　(B) gaseous

　　(C) separate

　　(D) new

　　404. Pheromones are substances that serve as chemical signals between members of the same species.

　　The word "serve" is closest in meaning to which of following?

　　(A) improve

　　(B) function

　　(C) begin

　　(D) rely

　　405. Pheromones are the predominant medium of communication among insects (but rarely the sole method) . Some species have simple pheromone systems and produce only a few pheromones, but others produce many with various functions.

　　The word "sole" is closest in meaning to which of following?

　　(A) obvious

　　(B) best

　　(C) only

　　(D) final

　　406. Some species, such as ants, seem to be very articulate creatures, but their medium of communication is difficult for humans to study and appreciate because of our own olfactory insensitivity and the technological difficulties in detecting and analyzing there pheromones.

　　The word " detecting " is closest in meaning to which of following?

　　(A) controlling

　　(B) storing

　　(C) questioning

　　(D) finding

　　407. Aphids, which are particularly vulnerable to predators because of their gregarious habits and sedentary nature, secrete an alarm pheromone when attacked that causes nearby aphids to respond by moving away.

　　The word "sedentary" is closest in meaning to which of following?

　　(A) inactive

　　(B) inefficient

　　(C) unchangeable

　　(D) unbalanced

　　408. These innovations in manufacturing boosted output and living standards to an unprecedented extent;the average per capita wealth increased by nearly 1 percent per year-30 percent over the course of a generation.

　　The word "boosted" is closest in meaning to which of following?

　　(A) ensured

　　(B) raised

　　(C) arranged

　　(D) discouraged

　　409. Since the 1790's, North American entrepreneurs --- even without technological improvements --- had broadened the scope of the outwork system that made manufacturing more efficient by distributing materials to a succession of workers who each performed a single step of the production process.

　　The word "scope" is closest in meaning to which of following?

　　(A) value

　　(B) popularity

　　(C) extent

　　(D) diversity

　　410. As early as 1782 the prolific Delaware inventor Oliver Evans had built a highly automated, laborsaving flour mill driven by water power.

　　The word "prolific" is closest in meaning to which of following?

　　(A) efficient

　　(B) productive

　　(C) self-employed

　　(D) progressive

　　参考答案：A D C B C D A B C B

　　以上就是托福词汇题精选试题，考生可在平常复习中进行参考训练以提高自己的考试水平，祝大家取得好成绩。