Act 1 begins at the place where is in front of a church and a market. A church is where higher-class people often go and a market is where lower-class people go. So we can view the church as a symbol of upper class and the market symbols for lower class. It is the place in front of them makes it possible for people from different classes to meet each other. However, in addition to the place, the summer rain is also important. The rain brings people into the place and so they can have longer conversations, or they may just pass by.
Besides, the division between classes is very clear. 'THE FLOWER GIRL. I aint done nothing wrong by talking to the gentleman.' ' dont let him charge me.' Really she did not do anything, but social criticism makes her afraid. She even thinks it may be incorrect to talk to a gentleman.
As to Eliza herself, apparently she is poor. We can know that from her job. Also we can know more about from her room. She collects the portrait of an actress and a fashion plate. This suggests that though she is poor, she tries to be fashionable by her own way. She keeps the birdcage, which is taken as a memorial. It shows how affective she is. Besides, she can not sleep without putting on many clothes, and she does not take a shower before go to bed. It means she does even not have enough money to buy a heater, and we can know she is poor and of low social class.
There is something about Eliza that is related to her class. She always says she is a poor girl. I think she hopes others feel sympathetic for her and but flowers from her.
Then we can see the differences how the gentleman and the note taker treat her. When she asks the gentleman to buy flowers, though he does not think he has change with him, he still tries his pockets and tells her ' theres a good girl.' He protects her when he thinks the note taker as a copper's nark. He is really nice to her. But the note taker, he calls her silly girl at the first sentence he says. And scolds her to cease the disgusting sounds then. He is quite impatient to her.
I think this act characterizes the three important roles in the play, and give us some ideas of how their attitudes toward one another