问题是 这样的， LZ找不到重点
Evaluate the effectiveness of goverment imposing an indirect  tax on a demerit good such as cigarettes.
  In your answer you should illustrate the effect(with  the use of a diagram)
   - The quantity of good sold
   - The price buyers pay
   - The amount sellers receive
   - The size of the deadweight loss

LZ认为大概和deadweight loss 有关，希望大家多多指点解惑。