特里芬教授在《2000年国际货币制度》一文中指出国际货币制度改革的根本出路在于（）。

在互成角度的两个共点力的合成实验中，其中的三个实验步骤如下：

（1）在水平放置的木板上垫一张白纸，把橡皮条的一端固定在木板上，另一端拴两根细线，通过细线同时用两个弹簧测力计互成角度地拉橡皮条，使它与细线的结点达到某一位置O点，在白纸上记下O点的位置和两弹簧测力计的读数F₁和F₂；

（2）在纸上根据F₁和F₂的大小，应用平行四边形定则作图求出合力F；

（3）只用一只弹簧测力计通过细绳拉橡皮条，使它的伸长量与用两只弹簧测力计同时拉时相同，记下此时弹簧测力计的读数F'及其方向。

以上三个步骤中均有错误或疏漏：

（1）中是________________________________；

（2）中是________________________________；

（3）中是________________________________。

阅读理解。

     We produce 500 billion of plastic bags in a year world-wide and they are thrown

away polluting oceans, killing wild-life 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 3months,

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 ground 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

额窦引流不畅的主要原因是（）。

A.额隐窝气房过度发育

B.鼻丘气房过度发育

C.Haller气房

D.中鼻甲根部过度气化

E.筛泡过度气化

焦炉煤气比高炉煤气对人有更大的伤害性。