[交流] Funny English quiz in everyday（NO.18）

Previously
Q: What thing is lighter than air that any person can hold in a second or in a minute but never in an hour?

A: A breath.

Today’s Question
Why did the man put wheels on his rocking chair?

We will hold this column everyday, the one who write the right answer first can earned 1 BB.
If u missed it this time, please come on and come here early, then use your smart head to find the answer.
I will give u the right answer in the column tomorrow.
So good luck to u!