Questions 4 to 7 are based on the following conversation. At the end of the conversation, you will be given 20 seconds to answer the question
Now, listen to the conversation.
When was the tunnel opened to the public

A．To illustrate the important role and function of the assignment desk.
B．To give us a brief introduction of their working conditions.
C．To exemplify the cooperation of all sections in the company.
D．To emphasize the mission of the correspondents.

A．Human beings can control their tears shedding much better than animals.
B．Only human beings respond to emotions by shedding tears.
C．Only human beings shed tears to get rid of irritating stuff in their eyes.
D．The animals’ tears are the response to physical or chemical stimulation.