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问题 选择题

用NA表示阿伏加德罗常数，下列叙述正确的是[ ]

A.标准状况下，2. 24 L Cl2与足量的稀NaOH溶液反应，转移电子总数为0.2NA

B.某CH3COONa溶液中含有1 mol CH3COO-，则Na+数目等于NA

C.一定条件下，将1 mol N2与3 mol H2混合反应后，生成NH3分子的数目为2NA

D.常温常压下，46 g NO2与N2O4的混合气体中含有的原子总数为3NA

答案

答案：D

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.\

6（）

A. getting by

B. getting on

C. getting through

D. getting over
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判断题

目前在省调、地调，地调接入调度数据网广域网出口处均配置硬件防火墙进行安全隔离，目的是为了防范黑客及恶意代码等对电力二次系统的攻击侵害。
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