Achoo

It's weird when somebody sneezes in class and nobody says anything for fear of breaking the language pledge.

In fact, I'm pretty certain there isn't even a way to say "bless you" in Chinese.

Instead, they say the following:

Sneeze once, somebody is saying nice things about you;
Sneeze twice, somebody is scolding you;
Sneeze three times, somebody is thinking about you;
Sneeze four times, you've caught a cold.