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问题 多项选择题

为了实现在同一衡器上对各种质量重物的重力力矩都能相平衡，可以采用以下几种方法（）

A.改变平衡物的质量

B.改变平衡力力臂

C.改变平衡方式

D.利用偏心轮等平衡物来实现自动平衡

答案

参考答案：A, B, D

单项选择题

国际上饭店业的食品饮料成本率一般为()，在我国饭店业中餐饮原料的成本率要高一些。

A.5%—15%

B.20%—30%

C.30%—35%

D.40%—55%
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听力题

根据短文内容和首字母的提示，把所缺单词完整地填写在短文后的横线上。

Nowadays, it’s common to keep dogs as pets. We can often see dogs’ owners taking them for a walk. But have you h 小题1: of taking penguins for a walk? Here i 小题2:  a piece of news from Japan. In Tokyo Zoo, penguins go out for a walk in line every day. It is said that this can make them happy and stop them from being homesick(想家的).The penguins in the zoo didn’t eat as

w 小题3: as they did in South Pole(南极) and they were u 小题4: to the keepers when they first got to the zoo, maybe they were not used to the life in the zoo. So the zoo keepers c 小题5:  up with this good idea. They just let them walk as they did in South Pole. Now, all these penguins have become happy.
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