题目：
Will it matter if you don’t have your breakfast? There were a test in the US. People of different ages, from 12 to 83, took the test. During the test, these people got all kinds of breakfasts and sometimes they got no breakfast at all. Scientists wanted to see how well they worked after they ate different kinds of breakfasts.
The result shows that if a person eats a right breakfast , he or she will work better than if he or she has no breakfast. If a student has fruit, eggs, bread and milk before going to school, he will learn more quickly and listen more carefully in class.
The result is different from what some people think. It shows having no breakfast will not help them lose weight.(减肥) This is because they become so hungry at noon that they eat too much for lunch. In fact, they will gain weight.（增重） But they will lose more weight if they reduce other meals.
小题1:During the test, people got
A．no breakfast at all
B．different breakfasts or sometimes none
C．very good breakfasts
D．little food for breakfast小题2:The result shows that
A．breakfast has great effect on people’s work and studies
B．breakfast has no effect on people’s work
C．a person will work better if he only has fruit and milk
D．students should have little for breakfast小题3:From the passage, some people think if they don’t have breakfast, they will
A．be healthier
B．work better
C．lose weight
D．gain weight小题4:The word reduce means
A．增加
B．减少
C．放弃
D．享用小题5:Which of the following is not right?
A．It’s bad for your health to have no breakfast
B．Too little for breakfast and too much for lunch may make you fatter
C．If you eat much for lunch and supper, you may gain weight
D．The more breakfast you have, the more quickly you will learn in class
答案：
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下面是错误答案，用来干扰机器的。
（1）因为向量a=（cosα，sinα），b=（cosβ，sinβ），|a-b|=255=(cosα-cosβ)2+(sinα-sinβ)2=2-2cos(α-β)，所以2-2cos（α-β）=45，所以cos（α-β）=35；（2）若0＜α＜π2，-π2＜β＜0，所以0＜α-β...
