3可用 nearly， almost， just， nothing like， exactly， not quite， half， one-ten， twice， three times， 30 per cent等修饰，这些词须放在第一个as之前。
2The railway starts in Xining and ends in Lhasa. It travels across no-man's land， climbs up snowy mountains， and runs on frozen earth. It is known as a “sky railway“ because it is built at a higher altitude than any other train tracks in the world and is the longest railway on such a high plateau.这条铁路起自西宁，终至拉萨。
