why这个特殊疑问词的意思是“为什么”,通常是对原因进行提问。

如:He went to the United States because he wanted to study there. 他去美国因为他想去那里学习。如果对because提问,可以是Why did he go to the United States? 而这句话的同义句可以是What did he go to the United States for?