We went back to the street and to the house in front of we had found the BlackBerry cell

问题补充：

We went back to the street and to the house, in front of we had found the BlackBerry cellphone.

A. it

B. which

C. that

D. what

答案：

A. it

(答案→)B. which

C. that

D. what

解析：本题修饰house是一个定语从句，先行词表示的是一个地点，我们可以用介词+关系词which来连接从句，故本题选B。