Question

【题目】It has been three years since I ______ a teacher.

A. become B. became C. becoming D. to become

Answer 1

【答案】B

【解析】

句意：自从我成为一名老师以来，已经三年的时间。since引导一般过去时态的从句，表示自……以来，结合语境可知下文从句描述的是过去某时的动作，故用一般过去时态，A. become变得，一般现在时态；B. became变得，一般过去时态；C. becoming变得，现在进行时；D. to become变得，动词不定式。根据题意，故选C。