Passage One Questions 26 to 28 are based on the passage you have just heard.

A．That more work is necessary for those facts.
B．That animals are helpless to healthy people.
C．That animals can also become friends of humans.
D．That they had a very successful discovery.

A．Colleagues.
B．Mother and son.
C．A teacher and a student.
D．A prospective employer and an employee.