听力原文如下：
Hallo, everybody, I am here, because I visited caves all over North America. Since you are going to study cave formations, Dr. Bow asked me to come and share some of my experiences with you. In addition to describing some of the technical aspects of the caves, I would convey the sense of adventure that cavers share. Recently, I visited the La Chagire cave in New Mexico, my dream has always been to discover a new passage way. I had a chance here, because La Chagire is so large that discoveries are frequently made there. The cave itself was not even discovered until 1986. However, people in that area had figured that there must be a cave nearby, because of the strong wind that blew from behind the huge rock that covered the entrance. Enormous amounts of air enter and exit the cave in order to maintain balance of the pressure with the side air. When I climbed into the cave, I had to fight 45 mile per hour winds. After all that effort, I had to be extremely careful maintaining my energy level. People who are tired tend to be careless, and may be more concerned about getting out of the cave than taking care of it. There are formations in LaChagire that look like ocean waves, Christmas trees and other stuff no one has ever seen before. Caves are normally created by carbonic acid that trickles down from above, but this cave sculpted out by very powerful sulfuric acid that wells up from below.
题目：Q49. What did the speaker say about the cavers who get tired?
选项：
49. (A) They are more likely to damage the cave.
(B) It’s hard for them to stay awake.
(C) They tend to break their equipment.
(D) They may imagine seeing things that aren’t really there.
答案：A， 偶对着黄色背景的这句话看了半天，虽然有“不小心想摆脱”的意思，但并没有说要“破坏洞”的意思啊？虽然相比较四个选项而言，还是A最好，但我还是想弄明白些，还请大家指点哦。 | 
