What goes up,must come down

What goes up,must come down what goes up must come down 英语翻译What goes up must come down yet my feet don"t touch the what goes up but doesn't come down? what alway goes up,but never come down? what goes up and never goes down? what goes up but doesn't come down?（什么只加不减?） What goes up and never comes down? what comes down but never goes up- what goes up when rain comes down What goes up but never comes down? what goes up but never comes down