How does Tom treat Becky Thatcher in Chapter 19, now that he's back? How does she treat him in return, and what is the underlying motive of this behavior?

After Aunt Polly kisses Tom good-bye, his moods are lifted. Seeing Becky Thatcher, he runs to her and apologizes for ignoring her and asks to "please make up." But Becky, still furious, simply tosses her head and passes on, sending Tom into a rage.

Please submit your questions one at a time.

I couldn't find anything about Becky Thatcher in Chapter 19.