单项选择题X 纠错
A.copper wire cables
B.satellite communication
C.optical fibers
D.laser and optical fibers
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单项选择题
A.Sunlight.
B.Nuclear.
C.Wind.
D.Electricity.
单项选择题
A.Most scientists are confident that the spacecraft will work well.
B.A more ambitious orbital flight will follow this mission.
C.The author is quite sure that this mission will make impossible technologies seem possible.
D.The key of the engineering of Cosmos I is building wings that can open and pivot.
单项选择题
A.It is a 3-ft. metal pod.
B.It has eight 35-ft. metallic wings.
C.It can fly an altitude above 260 miles.
D.When it flies back to Earth, it will fall into pieces.
单项选择题
A.the worship of the sun-god had clearly been the function of the temple
B.all living things celebrate the sunrise
C.the sunrise is the most magnificent of all phenomena
D.It is natural for man to worship the sun and he has always done so
单项选择题
A.had been abandoned by the Mayas about thirteen hundred years previously
B.had been occupied and developed by the Mayas about thirteen hundred years before
C.had been deserted by the Mayas as soon as the Spaniards arrived
D.was conquered by the Mayas thirteen hundred years ago
单项选择题
A.The realization that this was only a time-consuming fantasy.
B.The glimpse of an important clue to future discovery.
C.A resolution derived from his fantasy that he must learn more about this great past city.
D.The locating of the mysterious Sacred Well.
单项选择题
A.He remained in the saddle for several minutes spellbound.
B.He immediately jumped down and went forward.
C.He waited until his bed was ready and then dismounted.
D.He rode to the mound and stared at the structure before him.