seven and a half percent是百分之多少?

seven and a half percent是百分之多少? one and one-half percent是百分之几 three-and-one-half percent是百分之几? one half of one percent是百分之几? 请问“seven and a half thousand”到底是多少? 为什么7:30是half past seven.而不是at a half past seven 英语翻译What percent of a half dollar is a penny ,a nickel ,and 百分之50是fifty percent还是fifty of percent half的用法是 one and a half years 还是one and a half year?half具体的用 Tom and Mike meet at half past seven.(对 at half past seven 提 是one year and a half还是a year and a half?为什么? month and a half