A company in Texas had patented a method for breeding it.

德克萨斯州的一家公司已为其培育方法申请了专利。

But for the last six years or so I've been using the patented retrospective revision timetable method and I've never looked back.

但是在过去的六年左右，我一直在使用已获得专利的回顾性复习法，而我从未回头。