They arrived at a farmhouse in front of

问题补充：

They arrived at a farmhouse,in front of

答案：

填 which ,in front of which相当于where~

======以下答案可供参考======

供参考答案1:

填 which

这个是 which 引导的非限定性定语从句，which 做介词短语 in front of 的宾语

供参考答案2:

They arrived at a farmhouse, in front of (which) sat a small boy.