得参加一个7天的英语写作培训班的翻译：Had to take part in a 7-day English writing course 什么意思？中文翻译英文，英文翻译中文，怎么说？

青云英语翻译

Have participated in a seven-day training course in English writing

Had to take part in a 7-day English writing course

Must participate in a 7 day-long English writing training class

It participated in a 7 -day training course on English writing

Had to take part in a 7-day English writing course