参考答案：A. The white whale, Moby Dick, symbolizes nature for Melville, for it is complex, unfathomable, malignant, and beautiful as weU. For the character Ahab, the whale represents only evil.
B. For the author, as well as for the reader and Ishmael, the narrator, Moby Dick is still a mystery, an ultimate mystery of the universe. inscrutable and ambivalent, and the voyage of the mind will forever remain a search, not a discovery, of the truth.