In this section, you will hear several passages. Listen to the passages
carefully and then answer the questions that follow.
Questions 11 to 14 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.
The ultimate purpose of the research is to______.
A．have a better understanding of the life of mosquitoes B．prevent human beings from being bitten by mosquitoes C．purify the environment D．keep people alert