下列有关遗传的叙述中，不正确的是
A．一只白羊和一只黑羊，生了一只白羊，则可确定羊的白毛是显性性状
B．男性产生两种类型、数目相等的精子，女性只产生一种卵细胞
C．男性把含Y染色体的精子只传给儿子，不传给女儿
D．父母为双眼皮，后代是双眼皮的概率可能为3/4
答案：A
两只白羊交配，生下黑羊，才能推断出白毛是显性性状，一只白羊和一只黑羊，生了一只白羊，无法推断出显性性状是白毛还是黑毛。
| 用方框内所给单词的适当形式填空。 | |
old, only several years 2________ than me. In fact, some of them looked older and seemed more like grown-ups. And some of them even didn't listen to me 3________ in class. The classroom was on the second floor and it was directly above the street. One day, I was writing on the blackboard 4________ I heard a sudden change in the noise behind me. There was a man standing in the room with half an apple in his hand. He looked 5________. "Who threw this?" he shouted, looking around the class. "I beg your pardon?"I said. "6________ threw this apple out of the window." he said, "It landed on my car." "Who threw an apple out of the window?"I shouted to the class. There was no 7________. "I want the one who threw this." said the man,"I will be waiting outside for you."And then he left, slamming (摔) the door. There was silence and I went on 8________ the lesson. At the end of every lesson, as the bell rang, usually the class were all gone before it finished 9________, leaving me saying "That's all for today," to an empty room. This time, when the bell went for the end of the lesson, no one 10________."That's all for today," I said, "You go first, sir." said one of the boys. It made a nice change, being first out. |