在进行性肌营养不良症患者发病中起主导作用的因素为_________即病理基因所引起的一系列酶及生化改变。
参考答案：遗传因素
Think and write. （根据主语人称，用be动词的正确形式填空）
1. — you a boy?
— No, I not.
2. The girl _____ Jack's sister.
3. The dog _____ tall and fat.
4. The man with big eyes____ a teacher.
5. ____ your brother in the classroom?
6. — Where _____ your mother?
— She at home.
7. How _____ your father?
8. Mike and Liu Tao _____ at school.
9. Whose dress _____ this?
10. Whose socks _____ they?
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