Not until Kentucky's Mammoth Cave had been completely explored in 1972____.
A. when was its full extent realized
B. that its full extent realized
C. was its full extent realized
D. the realization of its full extent
查看答案
【C6】
A. consoled
B. compacted
C. paid
D. bracketed
In the author's opinion,America's health system is____.
A. inefficient
B. feasible
C. unpopular
D. successful
It is implied in the passage that_____.
America's health system has its strengths and weaknesses
B. the US government pays medical bills for the poor and the elderly
C. some 46 million Americans do not have medical insurance
D. Europeans benefit a lot from America's medical research
【C1】
A. economy
B. horror
C. magnifier
D. element
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