What does Willy Rusell indicate that time has passed between the end of Act 1 and the beginning of Act 2?

The way she dresses ,her attitudes towards Frank and the lessons too are some changes that we have the opportunity to see during these acts.She changes her attitudes towards Frank because she can answer Frank in a different way.She feels more confident,she thinks being there make her improve her process of learning poetry.She also learns more about the world that she was trying to understand better at the beginning of the Act 1.Rita hasn't exactly changed but she is just 'acting' as if she had changed, I mean, she wants to show that having been to Summer School has influenced her not only in her wanting to dress up but also in her wanting to be called 'the new educated Rita.' She wants to be compared with the 'proper students' she has mentioned previously in the play.the fact that Rita read books and learned a lot about writers means that she is now 'well-read' but, unfortunately, this being 'well-read' can sometimes be confused with being educated and that is exactly what happened to Rita: by this moment in the play she thinks that her being well-read and her having increased her knowledge about literature mean that she is now educated.

Why didn't Rita go to Frank's dinner party?

What I

think is that didn't want to go to the party because the fact that she migth have share the whole dinner with people who would have anything in common either to share and to talk with Rita. And because she wuold have the opportunity to compare herself with those people in the party.What's more,she might have felt she was not at the same level. She probably felt like a kind of test and she was not ready for this. Frank tells her that he wanted her to be there. He says that people at the party would have seen her as someone funny, delighful and charming... When Rita listensto this, she feels really awful and bad. What she wants is not to be funny, she wants to be taken seriously and be able to take part in their seriuos conversations as if she were one of them. She says: 'I don't wanna spend the night takin' the piss, comin' on with the funnies because that's the only way I can get into the conversation...'

Her mother's words reflects the same feeling that Rita has,because she has no opportunty to leran at some moment in her life.I think these words made Rita encourages to go on and not to have the opprotunity to regret not making the effort to improve herself.