单项选择题


In this section you will hear everything ONCE ONLY. Listen carefully and then answer the questions that follow. Mark the correct answer to each question on your coloured answer sheet.
Questions 1 to 5 are based on an interview with an expert on the urban problem. At the end of the interview you will be given I0 seconds to answer each of the following five questions.
Now listen to the interview.

According to the expert, which of the following is NOT the reason for this problem

A.Immigration.
B.Unemployment.
C.Falling mortality rate.
D.Rising birthrates.