The old town has narrow streets and small houses are built close to each other . A. in wh

问题补充：

The old town has narrow streets and small houses are built close to each other .

A. in which

B. where

C. what

D. that

答案：

A. in which

B. where

C. what

(答案→)D. that

解析：考查定语从句，先行词为narrow streets and small houses，从句中缺少主语，故用关系代词that，选D。