正确答案: A

只含碳，氢元素   含有碳，氧，氢三种元素 含有碳，氢元素，可能含有氧元素 无法确定

题目：植物的光合作用可表示为：二氧化碳 + 水 → 淀粉 + 氧气。根据以上信息，下列关于淀粉组成的说法中正确的是（     ）

解析：C

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举一反三的答案和解析：

[单选题]AHello，everyone! It's that time of year again! Hualin's fantastic sale! You name it， and we have it at a very good price． Do you like them at low prices? We have sweat-ers in all colors at 50 yuan each! Do you need a bag for sports or school? We have great .bags for just 6 yuan! For young boys and girls， we have T-shirts in red， green，yellow， orange， blue and black for only 15 yuan! And socks in all colors for just 1yuan! And that-s not all． Can-t you believe it? Come down to Hualin and see by your-self!

an advertisement(广告)

解析：21．B【解析】根据文章整体内容推断是一则广告，所以选B项．

[单选题]23． The desk is _________．

near the window