Question

【题目】______ he was 12, Einstein had learned advanced mathematics by himself.

A. The first time B. At the time

C. By the time D. During the time

Answer 1

【答案】C

【解析】考查连词：A．The first time第一次做---的时候，B．At the time在…那个时候，C．By the time到…时候为止，D．During the time在那期间，四个选项BD不能做连词，A的意思不对，选C，句意：到他12岁为止，爱因斯坦已经自学了高等数学。选C。