下图结构的物质在下列生物体或细胞中肯定具备的是（） ["动物的肌细胞","烟草花叶病毒","结核杆菌","洋葱的表皮细胞"]
延长技术生命周期战略一般发生在技术革命周期的（）阶段。 ["成熟期或淘汰期","成长期或淘汰期","创新期或成长期","创新期或淘汰期"]
A non-return valve in the air delivery line near to the compressor must be （）type similar to the compressor discharge valve. ["the low inertia","the high inertia","the low velocity","the high velocity"]
如何判断草鱼鱼苗、鱼种的质量？
A （） in the air delivery line near to each compressor is essential. ["butterfly valve","globe valve","gate valve","non-return valve"]
东北地区鲤鱼和鲢鳙鱼种怎么培育才省钱？
