Aren't both "sit" and "wonder" verbs? Can two verbs come together like that?

Native speaker’s answer
Rebecca
While at their base forms these two words are verbs, within the structure of the sentence "sitting" and "wondering" are both present participles. I'd say the reason this works is that there's a sense of an omitted word like "and" or "here." So It could be read as "I'm sitting here wondering" or "I'm sitting and wondering," but they sound so natural together that it's fine if those words are omitted. Also, they give us very different information about what's happening, "sitting" indicates the position, and "wondering" tells us what he's doing while sitting. Ex: I'm standing looking out the window, and then I see a bird. = I'm standing there looking out the window, and then I see a bird. Ex: She was crying, trying to get out of doing her chores.