Questions 17 to 20 are
based on the following passage. At the end of the passage, you will be given 20
seconds to answer the questions. Now, listen to the
passage.
What is the concern of ordinary people about the "Greenhouse Effect"
A.Whether it can be detected and checked. B.Whether it will lead to widespread food shortage. C.Whether global warming will speed up in the future. D.Whether it will affect their own lives.