This is Taipei.
Patty - This is my first time to take a bus in Taipei.
You'll have to show me what to do.
Daisy - Sure.  Do you see this sign? It shows the bus number.
The bus stops at all these places.
patty - So which bus do we take?
Daisy - This is our bus number.
Patty - Does our bus stop at your home?

Daisy - It stops close to my home. We'll have to walk about a block.
Patty - When does our bus come?
Roger - Soon. We have to wait here for the bus with our number on it.
Patty - How much is the bus ride?
Brian - it's only NT$15.
Patty - That's cheaper than in America. When do we pay?

Brian - Sometimes you pay when you get on the bus.
Sometimes you pay when you get off.
Daisy - We'll show you a sign on the bus. The first character on it is shang.
  If the light behind that character is on, you pay when you get on the bus.
Roger - The second character is xia.
 If the light behind that character is on, you pay when you get off the bus.
Patty - Now I understand.
Daisy - Good!  Riding the bus isn't a mystery.
But maybe you'll find another one to solve!  You're a detective.
Roger told me about you!
Patty - Oh, here comes our bus!