As teacher you must believe that you can make difference to the lives of your students.A.

问题补充：

As teacher，you must believe that you can make difference to the lives of your students.

A. a；/

B. a；a

C. /；/

D. /；a

答案：

A. a；/

(答案→)B. a；a

C. /；/

D. /；a

解析：考查冠词。第一空用a表示泛指老师；第二空是固定词组make a difference起作用,有影响；句意：作为一名老师，你一定要相信你可以对学生的人生有影响。故B正确。