(衡阳市八中2008届高三模拟试题C篇)

Desert ants on their expeditions for food use clues to lead themselves in the homeward direction, but with few landmarks in the poor land, scientists have wondered how the insects always take the most direct route and know exactly how far to march.

The new study shows that counting their steps is an important part of the scheme.

Over the years, scientists have proposed several theories for how ants find their way home. One is that they do it like honeybees and remember visual clues, but experiments showed ants can travel in the dark. Another theory is that because ants run at a steady pace, they could time how long it took them to get to and fro. Other studies have shown that once ants find a good source of food, they teach other ants how to find it.

The ant “pedometer” technique was first proposed in 1904, but it remained untested until now. Scientists trained desert ants to walk along a straight path from their nest entrance to a feeder 30 feet away. If the nest or feeder was moved, the ants would break from their straight path after reaching the expected spot and search for their goal.

Try that on stilts. They glued stilt-like extentions to the legs of some ants to lengthen stride. The researchers shortened other ants’ stride length by cutting off the ants’ feet and lower legs, reducing their legs to stumps.

The ants on stilts took the right number of steps, but because of their increased stride length, marched past their goal. Stump-legged ants, meanwhile, fell short of the goal. After getting used to their new legs, the ants were able to adjust their pedometer.

64. What is the passage mainly about?  

A. Ants’ marching depends on counting their steps    

B. Desert ants know how to look for food                               

C. The secret for ants’ marching is known to all      

D. Ants know how far their food is

65. Apart from counting their steps, how can ants find their way?

A. By smelling                        B. By communicating     

C.By hearing                         D. By recognising wind

66.About the ant pedometer, we know that______.

  A. the technique is a recent discovery        

B. ants always walk along a straight path

  C. ants often change their nest to keep the pedometer

  D. the pedometer needs changing depending on new situations

67. According to the passage, the “stump-legged ants”_______.

  A. have longer legs than ones on stilts     B. have longer legs than the common ones

  C. need more steps to reach their goal     D. can arrive at their goal as usual