Similar points: they are all women, they are all dead, and they were all written by Shakespeare (some of them are not his original works).
Differences and reasons:
Portia: a fashionable Italian woman during the Renaissance, who took the initiative to find a sexual partner and would rather betray her father for her lover.
Ophelia: A traditional court woman who uses morality as a code of conduct and lacks fighting experience. When difficulties
defeat her worldview, she only resorts to madness and suicide. as the only means.
Miranda: She did not resent the hatred of the previous generation but married her enemy on the desert island where she was exiled. This reflects her naivety and lack of understanding of social reality. Image of woman.
Reason: Portia is an Italian woman influenced by the Renaissance, which is why she helps her lover but not her father. Ophelia strictly adheres to feudal morality and falls into a vicious circle of logical paradoxes, which is the reason for her madness and suicide. Miranda was deprived of the opportunity to know the world since she was a child, so her animal nature defeated her reason, so she chose to marry her enemy and betray her dead father.