Strangers can become best friends just as easy as best friends can become strangers.
陌生人可以变成最好的朋友，就像最好的朋友也可以变成陌生人。
知识点：
stranger n.陌生人；外地人；新手
a stranger to
1. 陌生人：She is a stranger to us.我们不认识她。
2. 外行：He is no stranger to property.对于房地产他绝非外行。
3. 新到某地的人：She was not a stranger to this place, she was educated here.她不是初来此地,她是在这里上的学。
4. 不习惯于某种感情、经历、状况、工作等：She is not a stranger to misfortune.她对不幸的经历并不陌生。