包粽子的叶子:For every hour they skate, each student raises ten yuan for charity. 句首for的用法是什么

For every hour they skate, each student raises ten yuan for charity. 句首for的用法是什么 every hour on the half hour是什么意思? every hour on the half hour 是什么意思？ every hour on the half hour是什么意思 They say that it`s good for our health to drink ____(八杯水) every day. every gour on the half hour 是什么意思？ I ( )for( )every night Miss Gao watches TV for an hour. every hour on the hour……（一个语段）是什么意思？ 英语中表示时间的短语："Every hour on the hour"是什么意思？