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GRE閱讀高頻機(jī)經(jīng)原文及試題：蝙蝠的回聲定位

蝙蝠的回聲定位

Echolocating bats emit sounds in patterns—characteristic of each species—that contain both frequency-modulated (FM) and constant-frequency (CF) signals. The broadband FM signals and the narrowband CF signals travel out to a target, reflect from it, and return to the hunting bat. In this process of transmission and reflection, the sounds are changed, and the changes in the echoes enable the bat to perceive features of the target.

The FM signals report information about target characteristics that modify the timing and the fine frequency structure, or spectrum, of echoes—for example, the target’s size, shape, texture, surface structure, and direction in space. Because of their narrow bandwidth, CF signals portray only the target’s presence and, in the case of some bat species, its motion relative to the bat’s. Responding to changes in the CF echo’s frequency, bats of some species correct in flight for the direction and velocity of their moving prey.

33.1. According to the passage, the information provided to the bat by CF echoes differs from that provided by FM echoes in which of the following ways?

(A) Only CF echoes alert the bat to moving targets.

(B) Only CF echoes identify the range of widely spaced targets.

(C) Only CF echoes report the target’s presence to the bat.

(D) In some species, CF echoes enable the bat to judge whether it is closing in on its target.

(E) In some species, CF echoes enable the bat to discriminate the size of its target and the direction in which the target is moving.

33.2. According to the passage, the configuration of the target is reported to the echolocating bat by changes in the

(A) echo spectrum of CF signals

(B) echo spectrum of FM signals

(C) direction and velocity of the FM echoes

(D) delay between transmission and reflection of the CF signals

(E) relative frequencies of the FM and the CF echoes

33.3. The author presents the information concerning bat sonar in a manner that could be best described as

(A) argumentative

(B) commendatory

(C) critical

(D) disbelieving

(E) objective

33.4. Which of the following best describes the organization of the passage?

(A) A fact is stated, a process is outlined, and specific details of the process are described.

(B) A fact is stated, and examples suggesting that a distinction needs correction are considered.

(C) A fact is stated, a theory is presented to explain that fact, and additional facts are introduced to validate the theory.

(D) A fact is stated, and two theories are compared in light of their explanations of this fact.

(E) A fact is stated, a process is described, and examples of still another process are illustrated in detail.

GRE閱讀詞匯精選之皺褶

corrugate　v.(使)起波浪形，起皺紋

corrugation　n.波浪形狀，起皺紋

crease　n.折縫，· 皺痕

crinkle　v.(使)變皺，· n.皺紋

crumple　v.弄皺，· 扭彎

furrow　n.犁溝，· 皺紋

pucker　v.起皺n.皺褶

ruck　n.皺褶，· 普通群眾，· 大量

ruffle　v.變皺，· 弄皺，· 激怒

rumple　v.弄皺，· 弄亂

shrivel　v.枯萎，· 皺縮

wizened　adj.干皺的，· 干巴巴的

wrinkle　n.皺紋，· 竅門

pursy　adj.　皺起的

pleat　n.(衣服· 上的)褶

tuck　v.　卷起，· 隱藏　n.　縫褶，· 活力

hem　n.(衣服· 或裙子的)褶邊

懊悔

compunction　n.懊悔，良心不安

contrite　adj.悔罪的，痛悔的

contrition　n.悔罪，痛悔

lamentable　adj.令人惋惜的，悔恨的

penitent　adj.后悔的，懺悔的

impenitent　adj.不悔悟的

remorse　n.懊悔，悔恨

repent　v.懊悔，后悔

repentance　n.悔恨

repentant　adj.對…感到悔恨的

rue　n.后悔，遺憾.

rueful　adj.后悔的，· 遺憾的

guilt　n.罪行，· 內(nèi)疚

GRE閱讀詞匯精選之柵欄,窩巢

banister　n.(樓梯的)欄桿

barricade　v.n.設(shè)柵阻擋,柵欄

coop　n.(雞、)籠、欄

corral　n.(牛、馬等)畜欄

fold　n.羊欄，· 畜欄，· v.折疊

byre　n　牛欄，· 牛棚

grille　n.(銀行，· 郵局柜臺上的)鐵柵

hurdle　n.跳欄，· 障礙

palings　n.籬笆，· 木柵欄

pen　n.圍欄，· 監(jiān)禁

rail　n.欄桿，· 鐵軌，· v.咒罵，猛烈指責(zé)

stockade　n.柵欄，· 圍欄

palisade　n　籬笆，· 柵欄

aviary　n.大鳥籠,鳥舍·

apiary　n.　養(yǎng)蜂場

hive　n.蜂房，· 忙碌之地

kennel　n.狗舍，· 狗窩

lair　n.野獸的巢穴，· 躲藏處

roost　v.n.棲息，· 鳥巢

nidus　n　巢，· 孵卵所

-沼澤,困境

marsh　n.沼澤地，濕地

mire　n.泥沼，困境

morass　n.沼澤地，困境　　v.陷入困境

quagmire　n.沼澤地，困境

bog　n.　泥塘,沼澤

dismal　a.　陰沉的,凄涼的,暗的　n.低落的情緒,沼澤

swamp　n　沼澤,濕地

dilemma　n.困境，左右為難

hot　water　n.困境

predicament　n.困境,窮境

strand　v　使擱淺,使陷于困境

straits　n.困難，窘境

plight　n.境況,誓約,困境　v.宣誓,保證,約定

GRE詞匯詞根：aunt

daunt　v.使膽怯，使畏縮

dauntless　adj.勇敢的，無畏的

undaunted　adj.不屈不撓的，無畏的

flaunt　v.炫耀，張揚(yáng)

gaunt　adj.憔悴的，瘦削的

haunt　v.常到，(鬼魂)出沒。(事情)縈繞心頭　n.常去的地方

haunting　adj.不易忘懷的

jaunt　v.短程旅游

jaunty　adj.愉快的，滿足的

taunt　v.嘲笑，譏笑

vaunt　v.吹噓，炫耀

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