只要煤气设备严密不泄漏，按《工业企业煤气安全规程》规定，允许负压操作。()
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CO是无色无臭气体，有毒性，属血液性窒息性气体。()
The opening of the Copernicus Science Center aims to______.
A. memorize the great Polish scientist
B. lobby the government for financing
C. raise Poles" attention on natural science
D. help revitalize Poland"s economy
The authors attitude towards wind power is one of______.
A. objectiveness
B. encouragement
C. criticism
D. satisfaction
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