A．Add extra oil to their bicycle parts．
B．Wear special cycling glasses．
C．Take public transportation．
D．Drive a car to their destinations．

A．When they grow up in a particular set of surroundings．
B．When they travel to another country that they ’re not familiar with．
C．When they become totally dependent on the rules of their social group．
D．When they start to learn a foreign language．

A．They are frequently questioned by people unwilling to accept them．
B．They differ greatly among different social groups．
C．They govern the behavior of people who are dependent on them．
D．They are clearly articulated and their impact is always understood．