Questions 22～25 are based on the following monologue.

What is the substance in cigarettes that causes cancer

A．The professor had written it.
B．It is the major text for the course.
C．It contains new sociological evidence.
D．The students from last year liked it.

A．the Byzantine Empire was a unique case in which the usual order of military and economic revival coming before cultural revival was reversed
B．after 810 Byzantine economic recovery stimulated a military and later cultural expansion that lasted until 1453.
C．the eighth-century revival of Byzantine learning is a phenomenon that is difficult to explain
D．the revival of the Byzantine Empire between the 8th and 11th Centuries shows cultural rebirth preceding economic and military revival reversed the commonly accepted order of progress