A．Universities don't pay much attention to academic achievement.
B．Professors assign too much work to students in a short time.
C．Communication failure appears between students and professors.
D．Students don't know the rules of the college they are attending.
A．Salt is quite necessary for people's health.
B．Eating too much salt could do harm to the heart.
C．The quantity of salt varies among different people.
D．People are launching a campaign to eat less salt.
A．Eating more salt means more heart attacks.
B．Less salt is sure to reduce many heart-related diseases.
C．Eating less salt may lead to high blood pressure.
D．It's not clear whether eating less salt will have good results.