What's wrong with Alex?

Alex was fussy the other day and cried for a little while. It turns out he had gas. Well, no one was more disturbed by this than Bella.

Bella: "What's wrong with Alex?'
Daddy: "I don't know, let me see"
B: "Is he frustrated? Do you know what frustrated means?"
D: "No, what does it mean?"
B: "It means angry and sad at the same time"
D: "Bella has a bigger vocabulary than most 3 yr olds.
Mommy: "Bella has a bigger vocabulary than you at this point."