Directions:
Suppose IA Ming has caught a flu. He wants you to write a note to your teacher and ask for leave for three days. Do not sign your name at the end of the letter. Use "Li Hua" instead. You do not need to write the address.

A．is a very harmful behavior that evolution failed to get rid of.
B．makes it hard for people to drive safely under its influence.
C．has to do with people’s desire to achieve pleasant feelings.
D．is understandable behavior because it dates back long ago.