问题
不定项选择题
有关糖类物质的叙述中，正确的是 [ ]
A．凡符合通式Cm(H2O)n的化合物都属于糖类，不符合通式 Cm(H2O)n的化合物都不是糖类
B．凡具有甜味的物质都属于糖类，凡不具有甜味的物质都不属于糖类
C．糖类物质只含碳、氢、氧三种元素，但含碳、氢、氧三种元素的有机物不一定是糖类
D．糖类物质有的有还原性，有的没有还原性
答案
CD
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有关糖类物质的叙述中，正确的是 [ ]
A．凡符合通式Cm(H2O)n的化合物都属于糖类，不符合通式 Cm(H2O)n的化合物都不是糖类
B．凡具有甜味的物质都属于糖类，凡不具有甜味的物质都不属于糖类
C．糖类物质只含碳、氢、氧三种元素，但含碳、氢、氧三种元素的有机物不一定是糖类
D．糖类物质有的有还原性，有的没有还原性
CD
Friends are very important in our everyday life. Everyone needs friends. We all like to feel close to someone. It is nice to have a friend to talk, laugh, and do things with. , sometimes we need to be alone. We don’t always want people . But we would feel lonely if we never had a friend. No two people are . Friends sometimes don’t get on well. That doesn’t mean that they no longer like each other. Most of the time they will and become friends again. Sometimes friends move away. Then we feel very . We miss them very much, but we can call them and write to them. And we can new friends. It is encouraging to find out how much we like new people when we get to know them. There’s more good news for people who have friends. They live longer than people who don’t. Why? Friends can make us feel happy. Being happy helps you well. If someone cares about you, you take care of yourself.
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