只有损失机会而无获利可能的风险叫做()。
A.社会风险
B.投机风险
C.责任风险
D.纯粹风险
参考答案:D
--- She's never spoken to a foreigner, _______?
--- Yes. She is active and can speak English freely.
A. is she
B.has she
C.isn't she
D.hasn't she
循环流化床锅炉磨损较严重的受热面是()。
A.水冷壁;
B.埋管;
C.过热器。