搜题请搜索小程序“爱下问搜题”
问题 单项选择题

医用湿式激光相机的打印系统包括（）

A.激光发生器、调节器、发散透镜、多角光镜、聚集透镜、高精度电机

B.滚筒、高精度电机、调节器、发散透镜、多角光镜、聚集透镜

C.控制板、激光发生器、调节器、单角透镜、聚焦透镜

D.干燥系统、’聚集透镜、高精度电机、激光发生器、滚筒

E.调节器、发散透镜、控制板、聚集透镜、铝基板

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.\

10（）

A.business

B.commercial

C.trading

D.exchanging
查看答案
单项选择题

工程造价控制应遵循的原则是()

A.最优化原则 

B.经济为主、技术为辅原则 

C.以决策阶段为重点进行建设全过程控制原则 

D.主动控制原则
查看答案