Engagement
Captain von Trapp has gotten engaged to the Baroness. Ironically, he doesn't love her as he does Maria, whom he's become deeply fond of as she has brought love back into his home.
Military
The Captain is obviously a military man and has gone quite far in his military career because of the discipline he insists on. Ironically, he enforces this discipline upon his children after his wife dies as a means to raising them "properly".
Liesl
The von Trapp children aren't fond of Maria when she first arrives as they misbehave. Ironically, when Liesl sneaks back into the home after being out with her boyfriend, Rolfe, Maria doesn't tell her father. This is the beginnings of trust being created between them.
The Captain
The Captain is a man who has built his career on taking orders as well as giving them. Following the chain of command has served him. Ironically, when he is told to report to the Third Reich this is an order he will not obey as he believes what they are doing is wrong. He won't have any part of it.
Baroness
Maria has become quite comfortable in her role with the family and has become somewhat of a constant. Ironically, when he Baroness sees that Maria is attracted to the Captain she easily convinces her to move back to the Abbey, even when Maria knows she doesn't want to go back.
