A．To stay in class.
B．To get another class.
C．To withdraw from class.
D．To miss just one more class.

A．Employee and employer.
B．Daughter and father.
C．Classmates.
D．Student and teacher.

A．How to care for expensive metal.
B．A standard unit for measuring weight.
C．The value of precious metals.
D．How to monitor the drug industry.