Sleeping
At the opening of the film, we see Walter sleeping. It symbolizes that Walter is a man who is dreaming. He is not in touch with the realities of the world and his family around him. He only sees what's inside of him for better or worse.
Wake Up Walter Lee
Ruth yells at Walter to wake up. It is a symbol that she is the realistic one in their marriage. The one who is keeping them going day to day while Walter lives away in his dreams of being a success in the form of being a wealthy, rich man.
Insurance Check
The insurance check that the family is waiting on for months is a symbol of their dreams being able to come true. It is a symbol of Walter's dream of becoming a success, Beneatha's dream of being a doctor, Ruth's dream of having a home with space and Lena's dream of providing a better life for her family. It is all wrapped up in this one check.
Pregnant
Ruth comes from the doctor's office to tell everyone that she is pregnant. Her pregnancy is a symbol to her that life is going to be even harder as she will now have another child to take care of in a cramp apartment and they will have to figure out how to afford it on top of that.
Booze
After Walter hears what his mother has done with the insurance money, he goes and begins to drink at his favorite bar. The booze he drinks is a symbol that he does not face his problems, but instead drowns his pain in a bottle so as to do away with having to do something about it.
