第二节 短文理解2
阅读短文，从各题所给的三个选项中选出最佳答案。

Mr. Smith had three brothers. When his mother’s birthday was coming, he and his brothers wanted to send her some gifts. Mr. Smith thought the gifts of his brothers were not good enough. He wanted to buy a better one. He heard about an interesting bird. The bird could talk in twelve languages and sing twenty famous songs. He bought the bird and had it sent to his mother. He bought the bird for＄50,000. The day after his mother’s birthday. He called his mother. "What do you think of the bird" he asked. His mother said, "Delicious (味道鲜美) !"

The word" they" in the part" not because they have to" stands for(代替)