Step-by-step explanation:
The initial observation that Clarisse makes about Montag's conversational characteristics is during the period they initially meet. What happened was: Montag starts to laugh after Clarisse asks if firefighters didn't use to put out fires. Because Montag laughed, Clarisse says, "You laugh when I haven't been funny, and you answer right off. You never stop to think what I've asked you."
Another comment from Clarisse happens the subsequent time they both meet: they are talking, and Clarisse desires to understand from Montag how he decided to become a firefighter. Moreover, she informs him he is not like other firefighters she has met. She adds, "When I talk, you look at me. When I said something about the moon, you looked at the moon last night. The others would never do that."
Clarisse is expressing she is fascinated by Montag because he doesn't behave like many people who blaze books for a living.