1.[单选题]Which of the following is true about the U.S. Navy underwater listening net-work?
A.It is now partly accessible to civilian scientists.
B.It has been replaced by a more advanced system.
C.It became useless to the military after the cold war.
D.It is indispensable in protecting endangered species.
2.[单选题]It can be inferred from the passage that _____.
A.new radio devices should be developed for tracking the endangered blue whales
B.blue whales are no longer endangered with the use of the new listening system
C.opinions differ as to whether civilian scientists should be allowed to use military technology
D.military technology has great potential in civilian use
3.[单选题]The underwater listening system was originally designed _____.
A.to trace and locate enemy vessels
B.to monitor deep-sea volcanic eruptions
C.to study the movement of ocean currents
D.to replace the global radio communications network
4.[单选题]The passage is chiefly about _____.
A.an effort to protect an endangered marine species
B.the civilian use of a military detection system
C.the exposure of a U.S. Navy top-secret weapon
D.a new way to look into the behavior of blue whales
5.[单选题]The deep-sea listening system makes use of _____.
A.the sophisticated technology of focusing sounds under water
B.the capability of sound to travel at high speed
C.the unique property of layers of ocean water in transmitting sound
D.low-frequency sounds traveling across different layers of water