key to variety

例句：

1. 1. The key to success lies in hard work and dedication.
   成功的关键在于努力和奉献。
2. 2. The keynote speaker was a renowned expert in the field.
   主题演讲者是一位在该领域享有盛誉的专家。
3. 3. The key to unlocking this door is to turn the handle clockwise.
   打开这扇门的关键是顺时针转动把手。