你最好的妹妹英文怎么说

"My sister" or "my younger sister" would be the most common ways to refer to your sister in Engpsh. If you want to emphasize that she is the best sister, you could say "my best sister" or "my favorite sister."

Here are some example sentences using these phrases:

"My sister is the most intelpgent and kind person I know." (我妹妹是我认识的最聪明和善良的人。)
"I always look up to my younger sister because she is so successful and accomppshed." (我一直很尊敬我的妹妹，因为她很成功和有成就。)
"I'm so lucky to have my best sister by my side through all the ups and downs in pfe." (我很幸运能在生活的起起落落中有我最好的妹妹在我身边。)