现在分词 preferring
例：
The man, preferring to walk, declined our offer of a lift to the post office.
过去分词 preferred
例：
Although cash continues to be widely accepted, credit cards have become the preferred mode of payment in many retail stores.
改 prefer 的词性的相关规则是：
双音节并第二音节是重音的单词，改为分词时重复结尾的辅音然后加 ing 或 ed 。
即
prefer => preferring
prefer => preferred
commit => committing
commit => committed
occur => occurring
occur => occurred
等等。
追问也就是说只要第二个音节是重读的，无论开音节还是闭音节，都双写末位的辅音吗？
追答对。
追问嗯嗯，谢谢！