小轿车的挡风玻璃设计成倾斜的，而大货车的挡风玻璃却是竖直的。下列与挡风玻璃设计角度无

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.\

3（）

A.realm

B.net

C.relation

D.web

下列现象中可用光沿直线传播解释的是（　　）

A．小孔成像

B．路灯下的影子

C．雨后彩虹

D．湖面上树的倒影

可燃液体之所以会发生一闪即灭的闪燃现象，是因为液体蒸发的速度较慢，所蒸发出来的蒸汽仅能维持短时间的燃烧，而来不及提供足够的蒸汽补充维持稳定的燃烧，故闪燃一下就熄灭了。

货物、技术进出口许可管理制度是我国进出口许可制度的主体，其管理范围包括( )。

A．禁止进出口货物和技术

B．限制进出口货物和技术

C．自由进出口的技术

D．自由进口中部分实行自动许可管理的货物、

简述”瀑布模型”与”原型模型”的差异？