单项选择题
A．no plants would grow on our planet B．earth would be thirty degrees colder C．man could not live on the earth D．all of the above answers are correct
A．not to see a doctor B．to pay doctors less money C．to let medical students have free or partly free medical education D．to forbid doctors to ask their patients for too much money
A．tuition in medical schools is high B．the price of medicine is high C．doctors are overpaid D．doctors must pay money to banks