Insert an appropriate homonym
It is fun to jump in the puddles when it _________.

Rains

The correct homonym for the sentence "It is fun to jump in the puddles when it _________" is rains.

• Reigns means to rule as a monarch.
• Reins are the straps used to control a horse.
• Rains means to fall in drops from the sky.

In the sentence "It is fun to jump in the puddles when it _________", the speaker is referring to the act of water falling from the sky, which is called rain. Therefore, the correct homonym is rains.