【题目】The infrastructure of a country is ________ makes everything run well, including things like transport, irrigation, electricity and schools.
A. which B. that
C. where D. what
在线课程【答案】D
【解析】考查表语从句。句意：一个国家的基础设施就是使一切运转正常的东西，包括运输、灌溉、电力和学校等。此处有实际意义表示“什么”，在表语从句中作主语用what引导，故选D。