题目

科学家通过对鼠进行多年的研究，积累了大量的遗传学资料。鼠的毛色有灰色和黑色两种类型，受一对等位基因R、r控制。尾有短尾和长尾的区别，受一对等位基因T、t控制。现有灰色短尾鼠与黑色长尾鼠杂交，F1均为灰色短尾。F1与黑色长尾鼠杂交，F2中灰色长尾:灰色短尾：黑色长尾:黑色短尾=1：1：1:1。请回答下列问题。 （1）鼠的毛色中显性性状是______,判断依据是_____________。（2）通过上述实验,______(填“能”或“不能”)说明短尾和长尾这对基因位 短文改错。     此题要求改正所给句子中的错误，按下列情况改正：该行多一个词：     把多的词用斜线（\）划掉，在该行写出该词，也用斜线划掉。     该行缺一个词：在缺词处加一个漏字符号（∧），在该行写出该加的词。     该行错一个词：在错词下划一横线，在该行右边横线上写出改正后的词。 It is almost six years after I began to studyEnglish. I'm glad to saying I'm getting on well with it. But first I met with a lot of difficulties.I couldn't get mostly of the sounds correct or remember the new word we had learned. In class I couldn't catch the teacher. I almost lose heart when my teacher encouraged me go on studying it. " English is an useful tool in building our country. You must study it well," he said. At the help of my teacher, I had made up my mind to study hard. 1. _____2. _____3. _____4. _____5. _____6. _____7. _____8. _____9. _____10. _____