per cent 和percent 的区别?because the moon has only an eightieth of the earth's mass,it require97 per cent less energy to travel the quarter of a million miles from the moon to earth-orbit than the 200 mile-journey from earth's surface into orbit.

per cent 和percent 的区别?
because the moon has only an eightieth of the earth's mass,it require97 per cent less energy to travel the quarter of a million miles from the moon to earth-orbit than the 200 mile-journey from earth's surface into orbit.