重点：听第二个说话人B说话，but 后面所说的话为重点，出题点往往在but后面。四级听力题中，But 后面的为重点的占95%,之前的为重点的占5%。
A: I suppose you've bought some gifts for your family.
B: Well, I've bought a shirt for my father and two books for my sister. But I've not decided what to buy for my mother. Probably some jewels.
Question: Who did the man buy the book for?
Answer: His sister.