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举一反三
【单选题】Animal studies are under way, human trial protocols are taking shape and drug makers are on alert. All the international health community needs now is a human vaccine for the bird flu pandemic sweepin...
A.
it has strong side effect to the elderly.
B.
it may turn ineffective in a short period.
C.
it is useless in preventing the virus.
D.
it hasn’t been tested in humans.
【单选题】有些海蚀洞的“天花板”上还有个大窟窿，阳光照进来，就像罗马的万神殿一样。这可能是因为顶部岩石本身质地脆弱，更易被()。也可能是海水挤入岩石裂隙时，原本在里面的空气被压缩，水填满洞隙下方，压缩空气便()洞顶，直至将洞顶击穿，形成天窗。依次填入划横线部分最恰当的一项是：()
A.
腐蚀、入侵
B.
侵蚀、冲击
C.
侵袭、攻击
D.
腐化、充盈