单项选择题
A．the bus and train fares in the US B．the ways of paying a taxi in the US C．the public transportation in the US D．the advantage of subways in the US
A．buy a monthly pass B．ask about the fare first C．agree on the amount of the tip D．pay by the exact change in coins
A．eat their food slowly B．help the host serve food C．serve each other at the table D．help themselves to more food