听一段材料，回答下面几个小题。
What is the purpose of the speech?
A. Stressing physical exercise.
B. Offering some advice on sleeping problems.
C. Telling people how to exercise.
Which of the following can cause sleeplessness?
A. Too much exercise in the evening.
B. Lack of sleep on weekends.
C. Eating cheese before going to bed.
What can we learn about sleeping pills?
A. It'll help relax.
B. It prevents sleeping.
C. It's useless for sleeplessness.