Green is the color of nature. And you can enjoy the colorful rainbow in sky after the ra

问题补充：

Green is the color of nature. And you can enjoy the colorful rainbow in sky after the rain.

A. the; the

B. /; a

C. /; the

D. a; the

答案：

A. the; the

B. /; a

(答案→)C. /; the

D. a; the

解析：句意；绿色是大自然的颜色。雨后你能在天空中欣赏到多彩的彩虹。结合语境可知前文泛指大自然，nature是抽象名词，不可数，泛指不用冠词。下文特指雨后的天空，故用定冠词，选C。