问题
选择题
孟德尔在豌豆杂交实验中，发现问题和验证假说所采用的实验方法依次是 [ ]
A．自交、杂交和测交
B．测交、自交和杂交
C．杂交、自交和测交
D．杂交、测交和自交
答案
答案：C
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孟德尔在豌豆杂交实验中，发现问题和验证假说所采用的实验方法依次是 [ ]
A．自交、杂交和测交
B．测交、自交和杂交
C．杂交、自交和测交
D．杂交、测交和自交
答案：C
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| Once there lived an old man in a town. He always 1 a lot of things, so his wife always had to say to him, "Remember this." One day he went on a long 2 alone. Before he went out, his wife said, "Now you have all these things. Take care of them." He went to the station, bought a ticket and got on the train with 3 . About an hour later, the conductor (乘务员) came to the old man and said, "Will you please 4 me your ticket?" The old man looked for his ticket in all his pockets, but he couldn't find it. He was 5 ."I can't find my ticket. I really bought a ticket 6 I got on the train," said the old man."I 7 you bought a ticket. All right. You don't have to buy another one," said the conductor. But he 8 looked worried and said, "You don't know 9 . If I can't find my ticket, I don't remember my 10 where I am going." | ||||
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