给定一段英文文本，返回单词数最多的前5个单词和它们出现的次数。
“Artificial intelligence (AI) is intelligence demonstrated by machines, in contrast to the natural intelligence displayed by humans and animals. Leading AI textbooks define the field as the study of "intelligent agents": any device that perceives its environment and takes actions that maximize its chance of successfully achieving its goals.”
1. "intelligence" - 3
2. "AI" - 2
3. "the" - 2
4. "and" - 2
5. "its" - 2