Meaning: After it rains, a rainbow might show up in the sky.
Choice of Words: Rain falls is a simple statement that describes the action of rain coming down from the sky. Rainbow appears is a description of a rainbow becoming visible after the rain.
Alternative Expressions
Raindrops dance, colors shine.
Meaning: This is a more poetic way to say that when it rains, a rainbow appears in the sky. The raindrops look like they are dancing, and the colors of the rainbow shine brightly.
Choice of Words: Raindrops dance" is a poetic way to describe the falling rain. "Colors shine" refers to the colors of the rainbow.
Water from the sky, a colorful surprise.
Meaning: This is a simple way to say that when it rains, a rainbow might appear in the sky. The rainbow is a surprise because it is not always there.
Choice of Words: Water from the sky" refers to the rain. "A colorful surprise" refers to the rainbow.