It can be inferred from the passage that______.
A. light waves could be used in a device similar to radar
B. radar was a practical application of a well-known principle
C. radar gready increased the effectiveness of the Royal Air Force
D. sound waves are reflected from a hillside under all conditions
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The CalPERS lawsuit indicates that
A. the NYSE did ignore its regulatory duties
B. John Reed should resign like his predecessor
C. the investors were dissatisfied with the NYSE
D. the exchange should have its board reelected
When a machine is______, suitable materials must be chosen for its parts.
A. building
B. build
C. to build
D. to be built
It has always been the ______ of our firm to encourage workers to take part in social activities.
A. campaign
B. procedure
C. policy
D. rule
A．donationB．conversionC．auctionD．introduction
A. donation
B. conversion
C. auction
D. introduction
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