单项选择题A．We will not have enough food to eat.B．All the oil that drives our cars will be used up.C．The earth will become too crowded.D．There will be little water left on Earth.

单项选择题A．Their behavior should be attributed to factors beyond their control.B．Their behavior should be attributed to internal factors.C．Their behavior should be attributed to external factors.D．Their behavior should be attributed to others.