Questions 16 to 18 are based on the passage you have just heard.

A. It’s amazing that anyone could move so fast.
B. Televisions mark the beginning of modem life.
C. Modem life is changing very fast.
D. It’s hard to remember the past.

A. Only when he has saved up enough money.
B. Only when he has grown dissatisfied with his simple shelter.
C. Only when he has satisfied his hunger.
D. Only when he has learned to build houses.