Cardcaptor Sakura, Season One

Yamazaki:
And speaking of quizzes... The first person to make such a question was a philosopher from Greece. The very first question was "What walks with 4 legs in the morning, 2 legs in the afternoon, and 3 legs at night?" and...

Chiharu:
Yeah, yeah.

(Chiharu begins to drag Yamazaki off, while Sakura thinks about the question)

Yamazaki:
And, the first person to get that question right was....

Sakura:
Hey, Yamazaki, what was the answer to that question?

(notices Yamazaki is gone)

Yukito:
A human. As a baby you crawl on 4, as an adult you walk on 2 and when old, you use a cane for 3.