Teachers are some of the most important professionals in the world. They are responsible_____（21）preparing future generations to become productive and honest citizens, who will_____（22）to society for the whole of their adult life.
Obviously, the most common reason_____（23）teachers decide to teach is the ability to make a difference. There are many professions that give people the ability to have a(n) _____（24）impact on the world and change people's lives, _____（25）few professions have a direct impact on_____（26）a better society as teachers do. People tend to_____（27）their teachers for years after they finish school, for good teachers can_____（28）their students to become something that they_____（29）thought they could be, or to work_____（30）a field that they thought they did not_____（31）.
Teachers are also important because they provide_____（32）for their students. In certain low-income areas_____（33）some students may not have both of their parents _____（34）, teachers can provide an important influence that helps their students make the right_____（35）, even when they are not in the classroom. Generally, teachers' impact on students can last all through their life.
23._____
A、what
B、why
C、which
D、how
【正确答案】：B
【题目解析】：连词辩析题。分析句子可知，空格处需填一个引导定语从句的连接词。根据句意可知，教师决定教书的最常见原因是能够改变现状。reason作先行词，定语从句表示某事物的原因，则引导词用why。故选B。
