蚕丝是蛋白质
你可以这么记,动物不能消化纤维,因此很少有动物能合成纤维,一般纤维都是来自植物
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- 2英语选择:Anna——the piano when I went to see her mother.
- 3He said"I haven't heard from him since May".
- 4已知双曲线中心在原点,一个顶点的坐标为(3,0),且焦距与虚轴长之比为5:4,则双曲线的标准方程是_.
- 5食物链中有机物质最多的是什么生物成分
- 6Victor usually went to school on foot last year.同义句)= Victor usually ________ _______school las
- 7蒙娜丽莎是世界上最杰出的肖像画.改双重否定句
- 8I often visit my grandparents on weekends.(对visit my grandparents on weekends提问)
- 9I go to school at haif past seven.
- 10a+b=3派/4 求(1-tana)(1+tanb)