(1)she has a lot of experience to deal with teengers' problems
(2)she has a lot of experience dealing with teengers' problems
相同点：（1）与（2）都是有非谓语动词做修饰语
不同点 (1)使用了动词不定式做后置定语,
（2）使用了现在分词做了状语.
可以把上面两个句子稍微变形状,看感觉如何
（1） She has a lot of experience that is used to deal with teengers' problems（定语从句）
She has a lot of experience of dealing with teengers's problems (OF 结构定语）
她有很多处理青少年问题方面的经验.
(2) Dealing with teengers' problems,She has a lot of experiences （现在分词做状语）
处理青少年问题,她有很多经验