Questions 17 to 20 are based on the following passage. At the end of the passage, you will be given 20 seconds to answer the questions.
Now, listen to the passage.
According to the speaker, the dry-cleaning store used to be a ______.

A．A light cigarette contains low nicotine and tar content.
B．Smoking a light cigarette is different from smoking a regular one.
C．Women who smoke light cigarettes want to get higher levels of nicotine.
D．Tobacco companies advertise cigarettes as "light" to obscure smoking risks.

A．The difference between dream and dreamless sleep of human beings.
B．Why animals with distinctive life style sleep differently.
C．Deep dream sleep of predators.
D．Stupid animals and smart animals.