Submitted by admin on Thu, 04/24/2014 - 22:47
definition:
A system for the detection of objects under water by emitting sound pulses and detecting or measuring their return after being reflected
sentence:
Out in the Atlantic, vast Japanese factory ships work nonstop, using modern sonar detection to spot the tuna shoals they sweep the ocean clean of fish.
difficulty:
easy
toefl frequency:
2