46. ___
A. Write a report about their activities.
B. Attend make-up classes with Dr. Webster.
C. Help find turtle eggs before they hatch.
D. Spend two hours working for the project.
47. ___
A. How people in rural areas preserved food.
B. The construction of icehouses.
C. An important industry in the nineteenth century.
D. How improvements in transportation affected industry.
48. ___
A. Modem technology for the kitchen.
B. Improved transportation systems.
C. Industrial use of streams and rivers.
D. Increased temperatures in many areas.
49. ___
A. Only wealthy families had them.
B. They were important to the ice industry.
C. They were built mostly on the east coast.
D. They are no longer in common use.
Audio 3 What point does the lecturer make about whales and sound pollution?___
A. Increased sound pollution means whales 'talk' more at night than during the day.
B. Research shows whales communicate to warn each other of sound pollution.
C. Whales may not survive in some situations where there is sound pollution.
D. Sound pollution from submarines has little impact on whales and other creatures.
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