[单项选择] We all admire the beautiful blue of a clear sky or the superb contrast between the brilliant white of the clouds and the skyblue between them. This colour, however, is not natural in the atmosphere; it is an optical effect(光学效应). When light encounters a cloud of small particles, it is diffused. This may be illustrated by a familiar example. When sunlight enters a darkened room through a gap in the blinds, it will appear as a brilliant ray of light. This is because there are tiny particles of dust suspended in the air. These, although normally invisible, catch and diffuse any strong light shining on them. The same effect can be seen in the sky when broken clouds hide the sun. Thus we can see that diffusion occurs owing to all sorts of impurities in the atmosphere. This explains all the delightfully varied shades of colour seen at different times of the day. White light is a mixture of all the colours of the rainbow or spectrum (光谱) , which, as Isaac Newton proved, can be s
A. particles of dust are suspended
B. tiny dust particles become visible
C. it is very bright
D. it becomes visible

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[单项选择] We all admire the beautiful blue of a clear sky or the superb contrast between the brilliant white of the clouds and the skyblue between them. This colour, however, is not natural in the atmosphere; it is an optical effect(光学效应). When light encounters a cloud of small particles, it is diffused. This may be illustrated by a familiar example. When sunlight enters a darkened room through a gap in the blinds, it will appear as a brilliant ray of light. This is because there are tiny particles of dust suspended in the air. These, although normally invisible, catch and diffuse any strong light shining on them. The same effect can be seen in the sky when broken clouds hide the sun. Thus we can see that diffusion occurs owing to all sorts of impurities in the atmosphere. This explains all the delightfully varied shades of colour seen at different times of the day. White light is a mixture of all the colours of the rainbow or spectrum (光谱) , which, as Isaac Newton proved, can be s
A. atmospheric impurities
B. molecules of gas
C. varied shades of color
D. different times of the day

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[填空题]He made it clear that he did not agree with all we came up with at the meeting.

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We all laugh. We all hurt. We all make mistakes. We all dream, That’s life. It’s a journey. Please follow these rules to make the journey of your life a journey of joy!
{{U}} (62) {{/U}} positive through the cold season could be your best {{U}} (63) {{/U}} against getting ill, new study findings suggest.
In an experiment that {{U}} (64) {{/U}} healthy volunteers to a cold or flu virus, researchers found that people with a {{U}} (65) {{/U}} sunny disposition were less likely to {{U}} (66) {{/U}} ill. The findings, published in the journal Psychosomatic Medicine, build on evidence {{U}} (67) {{/U}} a "positive emotional style" can help {{U}} (68) {{/U}} off the common cold and other illnesses.
Researchers believe the reasons may be both objective as in happiness {{U}} (69) {{/U}} immune function and subjective as in happy
A. which
B. whether
C. where
D. how

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