单选题
{{I}} Questions 17～20 are based on the following passage. You now have 20 seconds to read questions 17～20.{{/I}}
单选题
Which of the following statements about the rattlesnake is untrue?
【正确答案】
D
【答案解析】
单选题
What eventually happens to the skin of the rattlesnake?
【正确答案】
A
【答案解析】
单选题
How do naturalists regard the rattle of the rattlesnake?
【正确答案】
C
【答案解析】
单选题
What other species of snake moves its tail rapidly when it becomes agitated?
【正确答案】
B
【答案解析】 [听力原文] Questions <17>-<20> The rattlesnake,
often considered the deadliest of all North American snakes, has often been the
subject of research and discussion among naturalists. This snake earns its name
from the presence of rings of tough skin on its tail that remain when sloughing,
or the dropping off of skin occurs. Whenever a rattlesnake is agitated, it
begins to move its tail, a motion that causes the rings of hardened skin to make
a rattling noise. Most naturalists believe that this noise is an
involuntary reaction that results from the nervousness of the reptile; they do
not think that the rattlesnake is attempting to convey a warning to its possible
victim. Studies have revealed that the rattlesnake is the only venomous snake
that gives a signal before striking and, in fact, this reptile is the only
species that has rattles. However, both the bull snake and the fox snake also
vibrate their tails rapidly whenever they become nervous. Whether or not the
rattlesnake should be called “the gentleman among snakes” because of the noise
it makes before striking is an interesting question.