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问题 单项选择题

关于房地产市场吸纳周期的说法，错误的是( )。

A．吸纳周期是指房屋从准备租信到租售完成所需的时间

B．吸纳周期反映可供租售量全部被市场吸纳所需的时间

C．在新建商品房销售市场中，吸纳周期又称为销售周期

D．吸纳周期在数值上等于吸纳率的倒数

答案

参考答案：A

单项选择题

Most plants can make their own food from sunlight, (1) some have discovered that stealing is an easier way to live. Thousands of plant species get by (2) photosynthesizing, and over 400 of these species seem to live by pilfering sugars from an underground (3) of fungi(真菌). But in (4) a handful of these plants has this modus operandi been traced to a relatively obscure fungus. To find out how (5) are (6) , mycologist Martin Bidartondo of the University of California at Berkeley and his team looked in their roots. What they found were (7) of a common type of fungus, so (8) that it is found in nearly 70 percent of all plants. The presence of this common fungus in these plants not only (9) at how they survive, says Bidartondo, but also suggests that many ordinary plants might prosper from a little looting, too.

Plants have (10) relations to get what they need to survive. Normal, (11) plants can make their own carbohydrates through photosynthesis, but they still need minerals. Most plants have (12) a symbiotic relationship with a (13) network of what are called my corrhizal fungi, which lies beneath the forest (14) . The fungi help green plants absorb minerals through their roots, and (15) , the plants normally (16) the fungi with sugars, or carbon with a number of plants sharing the same fungal web, it was perhaps (17) that a few cheaters—dubbed epiparasites—would evolve to beat the system. (18) , these plants reversed the flow of carbon, (19) it into their roots from the fungi (20) releasing it as "payment.\

18（）

A. in time

B. overtime

C. at times

D. behind time
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单项选择题

用紫外线照射红色细菌的培养液，接种在平板培养基上，几天后出现了一个白色菌落，把这个白色菌落转移培养，长出的菌落全是白色的，这是（）

A.染色体变异

B.自然突变

C.人工诱变

D.基因重组
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