题目

阅读短文，选择正确答案Once a great boxer （拳击家）, Tom Brown, went to a restaurant（饭馆）for dinner. He put his bag near the door, but he was afraid that someone would take it. So he got out a pen and a piece of paper and wrote on it: “The great boxer, Tom Brown, left his bag here. He’ll come back in a few minutes. ” He put the paper on his bag and went to have his dinner. When he came back, his bag wasn’t there. But he found a piece of paper on the ground. It said: “A great runner took away your bag, and he will not come back. ”（    ）1．Tom 杂合子Aa连续自交n次，关于第n代（Fn）的说法错误的是（    ） A．杂合子所占比例为（1/2）n B．纯合子所占比例为1－（1/2）n C．隐性纯合子所占比例为1/2－（1/2）n+1 D．显性性状个体所占比例为1/2－（1/2）n