A．The visiting economist has given several lectures.B．Dr. Johnson and the guest speaker were schoolmates.C．Dr. Johnson invited the economist to visit their college.D．The guest lecturer’s opinion is different from Dr. Johnson’s.
A．The visiting economist has given several lectures.
B．Dr. Johnson and the guest speaker were schoolmates.
C．Dr. Johnson invited the economist to visit their college.
D．The guest lecturer’s opinion is different from Dr. Johnson’s.