人体受到某种抗原刺激后会产生记忆细胞，当其受到同种抗原的第二次刺激后
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A．记忆细胞的细胞周期持续时间变短，机体抗体浓度增大B．记忆细胞的细胞周期持续时间变长，机体抗体浓度增大C．记忆细胞的细胞周期持续时间变短，机体抗体浓度减小D．记忆细胞的细胞周期持续时间不变，机体抗体浓度减小
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据新华网报道，曾被称为“滇中粮仓”的昆明市宜良县北古城镇，提出了“城镇工业上山，优质农田下山”的发展模式。据此回答下列问题。小题1:该镇提出“城镇工业上山”的主要目的是
A．山区环境优美，空气洁净
B．山上地势高，不易受洪水威胁
C．促进产业结构升级，提高城市化水平
D．减少占用耕地面积，守住耕地红线小题2:该发展模式产生的不利影响可能有
①引发土壤次生盐碱化；②地质灾害增加；③建设成本增加；④城镇工业可用土地减少；⑤山区水污染加剧
A．①②⑤
B．②③⑤
C．②④⑤
D．①③④
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I hear many parents complain that their teenage children are rebelling （叛逆). I wish it were so. At your age you ought to be growing away from your parents. You should be learning to stand on your own feet. But take a good look at the present rebellion. It seems that teenagers are all taking the same way of showing that they disagree with their parents. Instead of starting acting independently, most of them are holding one another's hands for reassurance （放心). They claim they want to dress as they please. But they all wear the same clothes. They set off in new directions in music. But they all end up listening to the same record. Their reason for thinking or acting in such a way is that the crowd is doing it. They have come out of their cocoon （茧) into a larger cocoon. It has become harder and harder for a teenager to stand up against the popularity wave and to go his or her own way. Industry has firmly developed a market for teenagers. These days every teenager can learn from the advertisements what a teenager should have and be. This is a great roadblock for the teenager who wants to find his or her own path. But the roadblock is worth climbing over. The path is worth following. You may want to listen to classical music instead of going to a party. You may want to collect rocks when everyone else is collecting records. You may have some thoughts that you don't care to share at once with your classmates. Well, go to it. Find yourself. Be yourself. Popularity will come—with the people who respect you for who you are. That's the only kind of popularity that is really important.
The author's purpose in writing this passage is to tell______.A. readers how to be popular with people around B. teenagers how to learn to make a decision for themselves C. parents how to control and guide their children D. people how to understand and respect each other
According to the author, many teenagers think they are brave enough to act on their own, but in fact most of them______.A. have much difficulty understanding each other B. lack confidence C. dare not deal with any problems alone D. are very much afraid of getting lost
The author thinks of advertisements as ______to teenagers.A. instructive B. attractive C. beneficial D. influential
The main idea of the last paragraph is that a teenager should______.A. differ from others in as many ways as possible B. become popular with others C. find his real self D. rebel against his parents and the popularity wave
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Green is an important color in nature. It is the color of grass and the leaves on trees. It is also the color of most growing plants.
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B．a new solider
C．a young horse
D．a thumb小题2:A person who has a green thumb is a person ____.
A．whose garden is greener than others’
B．whose thumbs are in green color
C．who is good at growing plants
D．who is younger than his neighbors小题3:The author is actually talking about ____.
A．colors
B．language
C．politics
D．agriculture小题4: Which of the following statements is NOT true according to the passage？
A．In about the 16th century, a greenhorn meant an experienced soldier
B．The Green Revolution may have some connection with green thumbs
C．The green-eyed monster was probably created by William Shakespeare
D．The green-eyed monster can be used to describe a person who is jealous
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阅读下面一首唐诗，然后回答问题。
**山行即事**王质 浮云在空碧，来往议阴晴。荷雨洒衣湿，苹①风吹袖清。 鹊声喧日出，鸥性狎波平。山色不言语，唤醒三日酲②。
注释：①苹（pín）：一种水草。②酲（chéng）：酒醒后的困惫状态。诗的最后两句用了什么修辞方法？表达了作者怎样的思想情感？__________________________
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现有一幼鼠，先天无胸腺，此鼠的免疫状况是
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A．有全部的细胞免疫能力B．丧失一切免疫能力C．有全部的体液免疫能力D．保留部分体液免疫能力