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问题 选择题

下列关于达尔文的自然选择学说的叙述，不正确的是（　　）

A．自然界中各种生物都能产生大量后代

B．为获取食物和空间，生物之间要进行生存斗争

C．为适应环境，生物会主动产生有利变异

D．适应环境的个体会保留下来

答案

达尔文的自然选择学说，源于达尔文于1859 年发表的惊世骇俗的宏篇巨著《物种起源》，其主要内容有四点：过度繁殖，生存斗争（也叫生存竞争），遗传和变异，适者生存；达尔文认为，地球上的各种生物普遍具有很强的繁殖能力，而生物赖以生存的食物和空间是有效的，这必然导致生物在生活过程中生存而斗争，在生存斗争中，具有有利变异的个体，容易在生存斗争中获胜而生存下去．反之，具有不利变异的个体，则容易在生存斗争中失败而死亡．生物的变异是随机产生的，产生的变异可能对生物的生存是有利的，也可能对生物的生存是不利的．

故选：C

完形填空

缺词填空 先通读下面短文，掌握其大意，然后根据短文内容和所给首字母，在空格内填入一个适当的词，使短文意思完整。所给单词在题后横线上必须完整写出。（本大题共6分，每格0.5分）

There are four people in my family. Every day my parents are very busy t   1 to make money in order to pay the high tuition（学费）for my brother and me. They hardly say "I love you" or send f   2  to each other. Besides，my father has a bad temper（脾气）.It is easy for him to lose his temper w  3   he’s very tired from the hard work. I didn’t know whether there was love between them u 4_  one spring. At that time，my father suddenly got badly sick. My mother had to stay with him in the hospital for a month. When they r _5__ from the hospital，they both looked very pale . It s_ _6__  that both of them had a serious illness.

After they were back，my mother helped my father walk slowly on the country road every day in the morning and dusk（黄昏）. H __7 ，after two months my father still couldn’t walk by  h__8_  ．All of us were worried about him.

"Dad，how are you f _9__ now?"  I asked him one day.

"Susan，don’t worry about me.”he said i  10 a low voice.“I just like walking with your mom. I like this kind of life.”Reading his eyes，I know he loves my mother very much.

Maybe many people think love m _11___  flowers，presents and sweet kisses. But from this experience，I understand that love is  _12___，making life strong and warm.
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选择题

下列各组有机物只用一种试剂无法鉴别的是(　　)

A．乙醇、乙酸乙酯、四氯化碳　

B．苯、苯酚、己烯

C．甲酸、乙醛、乙酸

D．苯、甲苯、己烷
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