.menghua {
	background-attachment: fixed;
	background-image: url(images/GraphicMachine.jpg);
	background-repeat: no-repeat;
	background-position: left bottom;
}
.menghua2 {
	background-attachment: fixed;
	background-image: url(images/BgMachine.jpg);
	background-repeat: no-repeat;
	background-position: left top;
}