题干

The food here smells good, but what does it          like?

A:taste

B:touch

C:seem

D:feel

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A

同类题1

任务型阅读

    Are you ready for your exam?

    So, it's exam time again -have you done the necessary work to get good marks? Sleeping with the textbook under the pillow in the hope that knowledge will be magically absorbed into your brain as you sleep doesn't work. The best strategy is to space your practice out, rather than cram(突击学习)it all together.____!

    In an article, Tom Stafford, a lecturer in psychology and cognitive(认知的) science at the APF--University of Sheffield, advises, “If you organize five hours of study into one hour a day, you'll remember more than if you study for five hours a day.”

    ____—get pen and paper and start working. Students who can test themselves in advance will be better at getting back material from their memory and learning that material in the long run. You should start by reading a textbook using your favorite highlighter(荧光笔)____.Instead of just reading those, you basically try to test yourself on them.

    ____, but if you are still anxious, there's no harm in performing a personal ritual(仪式). In Japan, for example, it seems to be a tradition for students to eat Katsudon before a test.____. The name of the dish reminds people of the word “katsu”, meaning“ winning”. The bottom line is that you need to study, sleep well on the eve of the test, eat a nutritious meal, drink plenty of water and believe that your efforts will pay off. Good luck in your exam.

A. Don't rely on memory alone

B. That means hit the books early

C. Good revision should give you confidence

D. Then make flashcards of all the important concepts

E. They believe they could wash all the knowledge out of their head

F. This is a warm bowl of rice topped with egg and a slice of deep-fried pork

G. In different countries there are always those who swear by their “lucky underwear”

同类题2

阅读下面短文.

光的散射与丁达尔效应

光通过光学性质不均匀的介质时出现偏离原来传播方向,而沿侧向传播的现象,称为光的散射.在暗室里,将一束经聚集后的光线投射到胶体系统上,在与入射光垂直的方向上,可观察到一条明亮的光路,这就是丁达尔效应.产生丁达尔效应的实质是光的散射.

表1  分散系对可见光的不同作用


溶液

胶体

浊液

光路示意图

对光的主要作用

透射

散射

反射或折射

当入射光的波长略大于分散相粒子的直径时就发生光的散射.可见光的波长在400~760nm的范围,略大于一般胶体粒子的直径(1~100nm),因此当可见光束投射于胶体时,就发生光的散射,产生丁达尔效应.

对于溶液,分散质分子或离子更小,对可见光的散射作用很微弱;而当可见光束通过浊液时,由于分散质的粒子直径大于入射光的波长,主要发生反射或折射现象.

回答下列问题:

(1)产生丁达尔效应的实质是____ 

(2)制备Fe(OH)3胶体,在小烧杯中加入20mL蒸馏水,加热至沸腾后,向沸水中滴入5~6滴饱和的____ 溶液,继续煮沸至液体呈红褐色即可.

(3)胶体区别于其他分散系的本质特征是____ (填序号).

a.胶体有丁达尔效应        b.胶体粒子可以透过滤纸

c.胶体的胶粒带有电荷      d.胶体粒子的直径在1~100nm之间

(4)CuSO4溶液无明显丁达尔效应的原因是____