why u cry?

chin was weeping when i concentrated to teach a few other students to read aloud the rhyme while she was doing her worksheet.
"Why are you crying? Are you feeling sick?"
"No..."
"Then stop crying. You almost finish your questions, please, don't cry."
I have no time to comfort her or finding out the exact reason.
The class ended just a short while after that.
While waiting the students back home, I raised my question to her again, "Why u cried?"
"Is it my loud voice scares you?"
"... " she nodded her head.