问题
单项选择题
对限性性状进行选种时可采用（）选种效果最好。
A.性能测定
B.同胞测定
C.系谱测定
D.后裔测定
答案
参考答案：B
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对限性性状进行选种时可采用（）选种效果最好。
A.性能测定
B.同胞测定
C.系谱测定
D.后裔测定
参考答案：B
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| Many people say that they have seen flying saucers (飞碟) in the sky. 1 can these things be? Some people think that they are spaceships from other planets. Doctors 2 that perhaps they are only a weakness of the eyes. It is possible that they are our own planes 3 very high. Or are they birds with the sun's light on them? But some people say that they have seen them 4 . They have seen beings (人) get off them and walk around. They have 5 to those beings, sometimes in English. People have 6 photos of flying saucers and of these beings. We have seen the photos, but sometimes the people had to take them in a 7 . Children have seen flying saucers, and even dogs have seen them. Perhaps we do not think that the 8 of children, or dogs are important. But school-teachers have 9 seen them and Air Force officers and 10 policemen. Must we not listen to these people? | ||||
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