[填空题]If you look to the left, you will see a river of great (wide)（）.

[填空题]If you look to the left, you will see a river of great (wide)（）

[单项选择]Did you ever wonder why you see the colors you do or if other animals see the same colors that you see We see light that bounces off of things around us. When the light enters our eyes, special cells tell our brains about the light. These cells are called photoreceptors. Light is made of little bits called photons. When the sun shines, trillions and trillions of these little bits of light fall on the earth. The photons bounce off of almost everything and some of them enter our eyes. Those bits that enter our eyes allow us to see. So, where does the color come from Starting in the 1600s with Sir Isaac Newton, scientists have believed that there are different kinds of photons. Different types give rise to our sense of colors. The different photons are said to have different wavelengths. Sunlight contains all the different wavelengths of photons. The visible wavelength colors can be seen when you look at a rainbow. Raindrops acting as natural prisms produce the colors.
A. Red, white, and blue.
B. Red, green, and yellow.
C. Red, green, violet.
D. Red, green, blue.

[填空题]You see him when you feel bad.

[填空题]Caribbean Islands
What would you see if you took a cruise to the Caribbean Islands Palm trees and coconuts (椰子) White beaches and clear, blue ocean Colorful corals (珊瑚) and even more colorful fishes and birds
You bet. There are thousands of islands in the Caribbean Sea. They are famous for their warm, tropical climate and great natural beauty.
The Caribbean Islands form a chain that separates the Caribbean Sea from the rest of the Atlantic Ocean. (1) Many of the islands were formed by the eruption (爆发) of ancient volcanoes (火山). Others are low-lying coral islands that gradually rose from the ocean.
The Caribbean Islands are known by several names. (2) The explorer Christopher Columbus called the islands the Indies in 1492 because he thought he was near the coast of India. Later, Spain and France called the islands the Antilles.
There are four large islands in the Caribbean Sea. (3)