♪ The Earth BEGAN to cool
The Big Bang Theory Season 12, Episode 19
♪ The Earth BEGAN to cool ♪
The Big Bang Theory Season 5, Episode 10
♪ The Earth BEGAN to cool
The Big Bang Theory Season 5, Episode 15
♪ The autotrophs BEGAN to drool,
Neanderthals developed tools ♪
The Big Bang Theory Season 12, Episode 13
I BEGAN to see
a white light.
The Big Bang Theory Season 7, Episode 7