吹灰气有()锅炉燃烧()或有炉烟与炉灰从炉内()时,禁止吹灰。
参考答案:缺陷;不稳定;喷出
My mother felt very ______ when she heard the news. [ ]
A. surprise
B. surprising
C. surprised
D. to surprise
阿罗的不可能性定理说明了什么问题?