
So, Alex,
what's the TOPIC of your dissertation?
The Big Bang Theory Season 6, Episode 3

...to introduce
an alternate TOPIC of conversation.
The Big Bang Theory Season 4, Episode 7

Oh, my, that's an uncomfortable TOPIC.
The Big Bang Theory Season 6, Episode 23

If we're going to change the TOPIC
from jellyfish...
The Big Bang Theory Season 6, Episode 20

- New TOPIC.
- Mm.
The Big Bang Theory Season 2, Episode 9