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 iow-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.

第（21）题选查看材料

• A.of
• B.in
• C.for
• D.to