Private companies have little interest in producing flu vacc

Private companies have little interest in producing flu vaccines because of_____

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From the text we can see that the author seems _______。

From the text we can see that the author seems _______。 A.optimistic B.pessimist

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造成全球气候差异最基本的因素是(  )

造成全球气候差异最基本的因素是(  )A.大气环流 B.太阳辐射 C.地面状况 D.人类活动

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宋应星的《天工开物》是一部(  )

宋应星的《天工开物》是一部(  )A.药物学巨著 B.农业百科全书 C.手工业技术专著 D.地理学专著

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