为什么英语时间都有两种表达方式呢?为什么要用两种表达方式呢?有什么区别和不一样么?比如说像下面这样

为什么英语时间都有两种表达方式呢?为什么要用两种表达方式呢?有什么区别和不一样么?比如说像下面这样
ten past seven / seven ten
a quarter past eight / eight fifteen
half past nine / nine thirty
a quarter to eleven / ten fortyfive
five to twelve / eleven fiftyfive
eight past three / three eight
a quarter past four / four fifteen
half past five / five thirty
a quarter to seven / six fortyfive
eight past thirteen / thirteen eight
a quarter past forteen / forteen fifteen
a quarter to seventeen / sixteen fortyfive