So, Alex,
what's the TOPIC of your dissertation?
The Big Bang Theory Season 6, Episode 3
If we're going to change the TOPIC
from jellyfish...
The Big Bang Theory Season 6, Episode 20
...to introduce
an alternate TOPIC of conversation.
The Big Bang Theory Season 4, Episode 7
Guys, our TOPIC is
"Encouraging Women in Science."
The Big Bang Theory Season 6, Episode 18
But I find that TOPIC irresistible so,
The Big Bang Theory Season 10, Episode 7