Normally a student would at least attend ______ classes each week.

A．will soon become a problem for people living in central England
B．has now become a threat to the local residents
C．can be stopped if proper measures are taken
D．is quickly changing the map of England

A．warn people whose homes are in danger
B．provide an effective way to slow it down
C．help to its eventual solution
D．lead to its eventual solution