Madam Qian furrowed her sparse eyebrows, "Isn't cleaning teeth simple? Don't we just brush off the outermost layer?"
"I knew you didn't know the correct way to brush, that's why I was patient in explaining it in detail," Su Qingyue replied, "Only brushing the top layer of the teeth. Aren't the top and inner surfaces of the teeth just as dirty?"
"So, there's a proper method to clean teeth..." Ding Er chimed in, "I've always found it troublesome, and only cleaned the surface..."
"Me too..." several others joined in.
Su Qingyue persuaded, "Sister Qian, you should brush your teeth the way I told you."
Madam Qian was astute, "I used your medicinal mud toothpaste, does it cost money?"
"No charge for trial. But, Sister Qian should give us a big smile first." She did not recognize Madam Qian, but had heard others calling her that when she was selling goods in the morning.
"This…" Madam Qian, aware that her teeth were unsightly, hesitated.