单项选择题
A．there is more food and water in space than on earth B．eating and drinking in space is a special problem C．astronauts can never eat or drink in a spaceship D．there is no food or water in a spaceship
A．you get much hungrier in space than you do on the earth B．you can't have water to drink in a spaceship C．astronauts must learn many new and different things D．you can't eat anything in a spaceship
A．it led to many other inventions B．man had no use for it then C．there were no wheels in nature D．all of the above