英文是fifty-one,
例如There are fifty - one cities and a large number of towns and villages The capital stands on both sides of a river , and has more than eighty thousand houses.
They were from fifty -one to one hundred yards long, and they gradually tapered from a nine-log breadth at their sterns, to a three-log breadth at their bow-ends.
它们的长度由100码逐渐缩为51码,由尾部9根原木的宽度缩小到头部3根的宽度。