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问题 单项选择题

中国营养学会建议的平衡膳食宝塔是向居民提出

A．食物分类

B．较理想的膳食模式

C．每日必需的食物摄入量

D．多样化的食物种类

E．具体的膳食食谱

答案

参考答案：B

解答题
已知：△ABC中角A、B、C所对的边分别为a、b、c且sinA•cosB+sinB•cosA=sin2C．
（1）求角C的大小；
（2）若a，c，b成等差数列，且
CA
•
CB
=18，求c边的长．
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选择题

— Why did the dinner party start so late last night?

— It was _____ that caused him to serve dinner an hour later than usual. 

A．we were late

B．we being late

C．our being late

D．because we were late
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