题型：任务型阅读 题类：常考题 难易度：普通
人教版（2019）高中英语必修第二册Unit 4 History and traditions同步习题3
Rainbows (彩虹) are one of the most beautiful works that nature creates. If you've ever seen one, consider yourself lucky.
Rainbows can be seen when light passes through raindrops, says Kristin Calhoun, a research scientist studying the conditions of weather.
When sunlight passes through raindrops, the light bends, as it enters a droplet. As it leaves the droplet, the light separates into different wavelengths (波长). The seven colors — red, orange, yellow, green, blue, indigo and violet — bend in seven different directions. Red light, for example, bends in a different way than violet light. It also explains why rainbows look like an arc (弧). Sometimes, however, rainbows can actually form a circle that you can see in a plane with the right conditions.
"There is an even better chance when the sun is at a lower level, early or later in the day," Calhoun says. And another key is to face the rain and have your back to the sun.
"Small showers and storms often form in late afternoon in this area," Calhoun says. "These types of showers often produce heavy rain, but remain isolated (孤立的) over the center of the island."
A．There are lots of stories relating to rainbows.
B．Rainbows are created by light through raindrops.
C．And each wavelength appears as a different color.
D．With the conditions just right, Hawaii gets lots of rainbows.
E．The best time to catch a rainbow is when it's sunny and raining.
F．But they can be seen only if you are in the right place at the right time.
G．This is why the person on the ground sees each color at a different location.
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