吸烟有害健康，原因是烟草含有对人体有害的物质(尼古丁)，这种物质主要存在于烟草细胞中的[]A．细胞壁上B．液泡中C．细胞核内D．细胞质中-八年级生物

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• 小刚同学在显微镜下观察到一些细胞，他判断是植物细胞。因为他观察到了[]A．细胞壁和液泡B．细胞壁和细胞膜C．细胞质和细胞核D．细胞膜和细胞质-八年级生物
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• 食物中储存的化学能来自于光能的转化，这种转化主要是通过植物细胞中的哪种结构实现的?[]A．细胞核B．细胞膜C．叶绿体D．线粒体-八年级生物
• 阅读理解。 This is the times of information technology. Pakistan (巴基斯坦) is also trying to keep up with th
• 制作洋葱表皮临时装片时，下面操作正确的是[]A．用餐巾纸擦拭载玻片B．将洋葱块直接放置在显微镜下观察C．用镊子将取下的洋葱表皮在水滴中展平D．染色时掀开盖玻片，滴入染液-七年级生物
• 阅读下面短文，根据短文内容完成下面表格。 Dreams may be more important than sleep. Some people don't need much slee
• 完形填空。 Many people say that they have seen flying saucers (飞碟) in the sky.1 can these things be?Some
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• 在制作洋葱表皮细胞临时装片时，正确的做法是[]A．尽量将材料撕得薄B．将盖玻片垂直于载玻片后迅速放下C．如有气泡，则用手轻压赶出D．盖上盖玻片后，可直接将稀碘液滴在盖玻片上-七年级生物
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• 菠菜放在开水里煮过后水的颜色变绿，而放在冷水中则不产生这种现象，原因是[]A．煮过后，绿色从细胞壁上褪了下来B．叶绿素溶解于热水而不溶解于冷水C．细胞质受热后产生绿色D．细-七年级生物
• 植物细胞既可以________，也可以________，这主要取决于细胞________水溶液的浓度和________浓度的大小。当周围水溶液的浓度________细胞液浓度时，细胞就失水；当细胞液浓
• 用盐拌黄瓜，黄瓜会出现________现象，若把已经________的黄瓜再放入清水中，则黄瓜又________，前者说明植物细胞可以________，后者说明植物细胞可以________。-七年级生
• 阅读理解。Here's the content (目录) of a book. 1. If you're interested in music, you can read &qu
• 完形填空。 India has sent1 first spaceship to the moon. Scientists sent the spaceship on October 22nd, 20
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• 将菠菜泡在开水中，开水会变绿，而把菠菜泡在冷水中，水不会变绿，这是因为开水破坏了细胞的[]A．细胞壁B．细胞膜C．细胞质D．细胞核-八年级生物
• 紫菜的叶绿体中，除含有叶绿素外，还含有大量的[]A．胡萝卜素B．叶黄素C．藻红素D．藻黄素-八年级生物
• 阅读理解。 Mails, games, music, news, chat rooms and shopping! The Interent is part of our life today. It
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• 阅读理解。 For most students, the time of exams is very stressful and difficult. Some people find exam ti
• 植物细胞的基本结构包括________、_________、_________和__________。-七年级生物
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• 先阅读短文，掌握其大意，然后从方框中所给的词中选出最恰当的10个，并用其适当形式填空，每个次限用一次。leafthen large learn ones grow thick hasmeanfirst
• 用方框中所给词语的适当形式填空，每词限用一次。(每词限用一次)。good, appear, interest, much, live in, write down, feed, ask, wide,
• 用所给词的适当形式填空。（必要时可加助动词或情态动词。） It's sometimes 1______ (report) that strange objects 2______ (see
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