The discussion was so prolonged and exhausting that（）the speakers stopped for refreshments.

A．a boy and a girl usually fight when they are together
B．people tend to be together more than they used to be
C．a lot of people being together makes fights likely
D．Railway leads the world to peace

A．satisfy the needs of all kinds of students simultaneously
B．focus on training students in various skills
C．encourage students to take as many courses as possible
D．make learning serve academic rather than productive ends