Questions 19 to 22 are based on the conversation you have Just heard.

A．They can defeat their opponent effortlessly.
B．Someone gave their information away to their rival.
C．Their opponent thinks the same way they do.
D．There is something unpractical in their plan.

A．Flies need less sleep than humans.
B．Humans need a similar amount of sleep with flies.
C．The amount of human sleep is determined by certain gene.
D．Flies can determine how much sleep they nee