A. To give an example of a bad reaction to penicillin.
B. To show how penicillin has changed over the years.
C. To emphasize the importance of antibiotics.
D. To explain why penicillin requires a prescription.

A. The students must follow all instructions exactly.
B. The students will be able to make choices about the laboratory work.
C. A great deal of equipment is available.
D. Homework must be handed in on time.