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问题 选择题

金鱼缸内放人金鱼藻的目的主要是（　　）

A．为金鱼提供食物

B．提高观赏价值

C．为金鱼提供隐蔽场所

D．增加水中的氧气

答案

绿色植物通过光合作用吸收二氧化碳，释放氧气，维持生物圈中的碳氧平衡．金鱼藻是一种多年生的沉水草本植物，养金鱼的人在金鱼缸中放入金鱼藻的主要目的是减少水中的二氧化碳，增加水中的氧．

故选D．

选择题

关于丙烯醛（CH2＝CH－CHO）的叙述中，不正确的是 [ ]

A．能发生银镜反应

B．与足量的氢气加成生成丙醛

C．在一定条件下可氧化成酸

D．可使溴水褪色

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填空题

CONVERSATION 2 (Questions 5-8)


The age when Miss Rowling started to write: (5) .
Miss Rowling considers herself very luck because she can (6) herself by writing.
Miss Rowling never really imagines a (7) audience when writing.
Miss Rowling (8) know where the ideas for the Harry Potter books came from.

CONVERSATION 2 (Questions 5-8)


The age when Miss Rowling started to write: (5) .
Miss Rowling considers herself very luck because she can (6) herself by writing.
Miss Rowling never really imagines a (7) audience when writing.
Miss Rowling (8) know where the ideas for the Harry Potter books came from.
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