给定一篇英文文章和一个主题单词，需要对文章中出现的所有该主题单词进行高亮或下划线处理。
主题单词: artificial intelligence
文章:
Artificial intelligence (AI) has been a hot topic this year. The rapid development of AI brings both opportunities and challenges. As for the future of AI development, it remains uncertain.
Artificial intelligence (AI) has been a hot topic this year. The rapid development of AI brings both opportunities and challenges. As for the future of AI development, it remains uncertain.