路由协议大体上可分为链路状态协议和距离矢量协议两种.其中,OSPF属于()链路状态协

题型:单项选择题

问题:

路由协议大体上可分为链路状态协议和距离矢量协议两种.其中,OSPF属于()链路状态协议。

A.距离矢量协议

B.链路状态协议

考点:通信工程师路由技术路由技术题库
题型:单项选择题

培养白喉棒状杆菌常用的培养基为()

A.罗氏培养基

B.普通培养基

C.吕氏培养基

D.厌氧培养基

E.沙氏培养基

题型:单项选择题

玻璃中含有SiO2,它是非金属氧化物,能与碱反应生成硅酸盐(SiO

2-3
),所以实验室盛装NaOH溶液的试剂瓶用橡皮塞而不用玻璃塞.写出SiO2与NaOH溶液反应的化学方程式______.

题型:单项选择题

阅读理解。

     We produce 500 billion of plastic bags in a year worldwide and they are thrown away polluting oceans,

killing wildlife and getting dumped in landfills where they take up to 1,000 years to decompose. Researchers

have been unsuccessfully looking for a solution.

     The 16-year-old Canadian high school student, Daniel Burd, from Waterloo Collegiate Institute, has

discovered a way to make plastic bags degrade (降解) in as few as 3 months. a finding that won him first

prize at the Canada-Wide Science Fair, a $ 10,000 prize, a $ 20,000 scholarship, and a chance to revolutionize

a major environmental issue.

     Burd's strategy was simple: Since plastic does eventually degrade, it must be eaten by microorganisms (微

生物). If those microorganisms could be identified, we could put them to work eating the plastic much faster

than under normal conditions.

     With this goal in mind, he grounded plastic bags into a powder and concocted (调制) a solution of

household chemicals, yeast (酵母) and tap water to encourage microbes growth. Then he added the plastic

powder and let the microbes work their magic for 3 months. Finally, he tested the resulting bacterial culture

on plastic bags, exposing one plastic sample to dead bacteria as a control. Sure enough, the plastic exposed

(暴露) to the live bacteria was 17% lighter than the control after six weeks.

     The inputs are cheap, maintaining the required temperature takes little energy because microbes produce

heat as they work, and the only outputs are water and tiny levels of carbon dioxide.

     "Almost every week I have to do chores and when I open the closet door, I have piles of plastic bags

falling on top of me. One day, I got tired of it and I wanted to know what other people are doing with these

plastic bags. The answer: not much. So I decided to do something myself." said Daniel Burd.

1. Daniel Burd won first prize at the Canada-Wide Science Fair because ____.

A. he found a new kind of microorganism

B. he contributed much to environmental protection

C. he found a way to degrade plastics in shorter time

D. he could encourage microbes growth in an easier way

2. Daniel Burd exposed one plastic sample to dead bacteria to ____.

A. make the live bacteria work better

B. test how effective his method was

C. know which bacteria worked faster

D. control the temperature in the process

3. Maintaining the required temperature takes little energy because ____.

A. plastics can get hot easily

B. microbes can produce heat themselves

C. much carbon dioxide is produced

D. the temperature can be controlled

4. Daniel Burd got his idea from ____.

A. his school textbook

B. the failure of researchers

C. his everyday work

D. the practice of other people

题型:单项选择题

如果速动比率低于1,则意味着短期偿债能力偏低。( )

题型:单项选择题

报验登记包括哪两个模块?

更多题库