Definition: In this task, you're given an article and an answer. Your task is to generate the fill-in-the-blank question for this answer based on the given article. The blanks are always at the end of the question, and can be filled with more than one word or phrase.
Input: Article: American schools do not have separate classes for boys and girls. If boys want to cook or to sew, they can learn these things in classes that are no longer just for girls. If girls want to repair cars, they can now learn this in school. Most students like to have boys and girls on the same baseball team. Many boys and girls dress alike in school. They were blue jeans and sport shirts. Some have long hair and some have short hair. Sometimes a boy has longer hair than a girl. Even the language is different. Students learn to say fire fighter instead of fireman, police officer instead of policeman, and letter carrier instead of mailman. A person does not need to be a man to fight a fire or to deliver the mail. Most people think that these changes are good. They give all people an equal chance to be happy and to do what they want to do with their lives. Fathers like to tell their sons that they can grow up to be president. Today, mothers can tell the same things to there daughters. 
 Answer: a police officer can be a policeman or policwoman

Students in American schools learn to say police officer instead of policeman because  _  .