Einstein’s most famous theory is we call the Theory of Relativity.A. whatB. thatC. whichD

问题补充：

Einstein’s most famous theory is we call the Theory of Relativity.

A. what

B. that

C. which

D. why

答案：

(答案→)A. what

B. that

C. which

D. why

解析：考查表语从句：句意：爱因斯坦的著名的理论是我们称之为相对论的东西，what引导的是表语从句，表语从句中缺少宾语，用what引导。句意：爱因斯坦的最著名的理论是我们称之为相对论的东西。选A。