If a stranger and you start talking when you are 2 feet apart, what will you do?

【答】apart 在本句用作副词，意为“（在空间方面）相距；相隔”，多指两个事物之间的距离，意思相当于away。例如：

The two factories are three kilometres apart. 两个工厂相距3公里。

The two buildings are 15 metres apart (from each other). 这两幢大楼相距十五米。

when you are 2 feet apart：指“你跟陌生人之间相隔2英尺的时候”。