问题 选择题

图为近地面某气压场中的受力平衡的风向图,图中字母a代表的是

A.水平气压梯度力

B.摩擦力

C.地转偏向力

D.近地面风向

答案

答案:C

题目分析:解答本题应首先判定水平气压梯度力,因为它最好判断,该力的特征是垂直等压线,并由低压指向高压,所以箭头d为水平气压梯度力。其次观察风向,由于是近地面图,所以风向应与等压线斜交,图中b、c、d均与等压线斜交,但a、b由低压指向高压,这不可能是风向,只有c为风向,这样与c方向相反的为摩擦力b,与风向相垂直的为地转偏向力a。故选C。

点评:本题难度较小,解答本题需明确以下几点:

(1)气压梯度力:垂直于等压线,从高压指向低压;

(2)地转偏向力:垂直于风向,北半球右偏。

(3)高空中的风:只受气压梯度力和地转偏向力作用,不受摩擦力的作用,最后与等压线平行。

(4)北半球风向右偏。

阅读理解与欣赏

阅读下面的文字,完成下题。

众所周知,蜥蜴俗称自然界中的“变色龙”。但是地处圣地亚哥的加利福尼亚大学最近的一项研究表明,热带比目鱼才是大自然真正的隐形高手。

这种鱼能在8秒钟之内把自身的颜色混同于任何一种周围环境。据科学家拉玛康德莱姆称。这是所发现的变色最快的比目鱼。拉玛康德莱姆在各种环境下对这种鱼进行了实验.结果令人惊讶。

比如.当他把这种鱼从海底泥沙中移到黑白相间的花格板上或圆点图案中时,比目鱼便迅速地“穿起”方块或圆点的“外套”。

更值得一提的是,一旦这种鱼在第一次试验中“识别”了某种图案.在第二次试验中它便能够在2秒钟之内复制出这种图案。这一特性为比目鱼在热带环境中生存提供了迅速的隐蔽条件。

拉玛康德莱姆认为这种比目鱼善变的秘密在于它的大脑和皮肤。首先,它的大脑细胞接受来自眼睛的视觉信息。识别出环境中的图形和颜色。然后这些细胞再向皮肤中的色素细胞发出信号。

比曰鱼的皮肤上覆盖着色素细胞。它们能够用至少六种不同形状的条纹复制图案。这些条纹包括圆点、圆圈和h图形等。这样,通过控制条纹的明与暗,比目鱼的大脑就能够在皮肤上进行“数学绘图”。

小题1:把下列判断分成四组.是热带比目鱼大脑特点的一组是    (  )

①接受来自眼睛的视觉信息②识别出环境中的图形和颜色③向皮肤中的色素

细胞发出信号④用条纹复制图案

A.①③④

B.①②③

C.②③④

D.①②④小题2:对本文所提供的信息,理解准确的一项是    (    )

A.就伪装的能力而言.蜥蜴远远不如比目鱼。

B.只有一种比目鱼能变色。

C.热带比目鱼是一切动物中变色最快的一种。

D.拉玛康德莱姆所做的实验中。有的侧重测量热带比目鱼复制图案的速度。有的侧重测试复制图案的条纹。

小题3:下列说法.符合原文意思的一项是    (    )

A.热带比目鱼所复制的图案,或由圆点组成,或由圆圈组成,或由h图形组成,或

由其他条纹组成.有多少种条纹就有多少种图案。

B.热带比目鱼所复制的图案.由包括圆点、圆圈和h图形等条纹组成。

C.热带比目鱼所复制的图案同任何周围环境一样.

D.只要有不同的条纹,热带比目鱼就能复制图案。小题4:下列说法,符合原文意思的一项是    (    )

A.只需8秒钟左右热带比目鱼便可通过自身颜色的改变,把自己隐蔽起来。

B.热带比目鱼第二次接触类似环境,不到两秒钟就可以将自己隐蔽起来。

C.热带比目鱼被置于黑白相间的花格板上或圆点组成的图案中时.能迅速地改变

自身颜色。

D.在热带环境或其它环境中,比目鱼都能迅速地隐蔽自己。这为其更好地生存提供了条件。

完形填空
完形填空。
     Mr.West intended to buy his wife a Christmas present, but he was always very busy, so he was
never 1  to find time to go to the shops. At last, when it was the week  2  Christmas, and the shops
were very crowded, he  3  that he could not wait any longer. He worked in an office, and    4   had
lunch in a restaurant, but one day he bought some sandwiches, ate them quickly and went out to a
big shop near his office during his lunch   5  .The shop was full of women, who were also buying
presents during their lunch hour.
      Mr.West stood politely at the edge(边)of a crowd of women who were   6   forward to try to
get to the people who were  7  necklaces and earrings. He tried to move forward slowly, taking his
turn with the others, but more and more women were   8  into the shop the whole time and pushing
selfishly past him.
      After half an hour, he was just as far from the people who were selling the necklaces as he had
been   9  he came in, and his lunch hour was coming to an end, so he decided to change his     10  
of doing things: he put his head down,  11   a sudden loud shout and started to push his way towards
the  12  of the crowd as hard as he could.
     The women around him became very   13  when they saw what he was doing, and began to scold
him."Why can't you behave like a gentleman?"they shouted.
     "Ladies,"he   14  them,"I have been behaving like a gentleman for the past half hour, and it has done
me no   15  ,so now I am starting to behave like a lady!"
( )1.A. sure
( )2.A. before
( )3.A. promised
( )4.A. never
( )5.A. hour
( )6.A. pulling
( )7.A. selling
( )8.A. going
( )9.A. where
( )10.A. habit
( )11.A. caught
( )12.A. center
( )13.A. patient
( )14.A. hated
( )15.A. treasure
B. certain
B. after
B. decided
B. sometimes
B. moment
B. pushing
B. buying
B. entering
B. until
B. way
B. made
B. end
B. angry
B. waved
B. good
C. able
C. till
C. agreed
C. seldom
C. minute
C. gathering
C. choosing
C. fetching
C. when
C. action
C. blew
C. front
C. surprised
C. explained
C. respect
D. possible  
D. within    
D. insisted  
D. usually    
D. second    
D. managing  
D. seizing    
D. coming    
D. even if    
D. sign      
D. gave      
D. back      
D. nervous    
D. answered  
D. present