题干

中心在原点,对称轴为坐标轴,离心率为2,实轴长为4的双曲线方程为____
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x24 \ufe63

同类题1

某同学在学习“细胞工程”时,列表比较了动植物细胞工程的有关内容,你认为有几处不正确
 
植物细胞工程
动物细胞工程
技术手段
植物组织培养植物体细胞杂交
动物细胞培养和融合单抗制备等
特殊处理
酶解法去除细胞壁
胰蛋白酶处理制细胞悬浮液
融合方法
物理方法化学方法
物理方法化学方法
典型应用
无病毒植物的培育、人工种子、种间植物杂交等
单克隆抗体的制备等
培养液区别
蔗糖是离体组织赖以生长的成分
动物血清不可缺少

同类题3

完形填空

    As I held my father's hands one night, I couldn't help but notice their calluses (老茧) and roughness. His hands tell the story of his life as a1, including all his struggles.

    One summer, I remember, a drought (旱灾) hit Ontario, turning it into a 2desert. On one of those hot mornings I was picking sweet com with my dad to fill the last3from the grocery store. Fifty dozen was all we needed, which4took twenty minutes. That morning, however, the process didn't 5quickly. After forty minutes of aimlessly walking in the field, we6 needed twenty dozen. I was completely frustrated (挫败的) and7. Dropping the basket heavily, I declared, “If the store wants its last twenty dozen, they can pick it themselves”. Dad8. “Just think, my little girl, only ten dozen left for each of us and then we're9.” Such is Dad----whatever problem he 10 he never gives up.

    11  the bad effects of the drought were felt all over our county. It was a challenging time for everyone,12Dad remained optimistic (乐观的). He 13to be grateful for other things like good health and food on our plates. Only then did I truly begin to 14Dad and his faith that guided us through the hard times.

    Dad is also a living example of real 15  From dawn to dusk, he works countless hours to 16our family. He always puts our happiness 17his own and never fails to cheer me on at my sports games 18his tiredness after long days. His loving and selfless nature has encouraged me to become more sympathetic (有同情心的) and19, putting others first.

    Dad, the life 20I have learned from you will stay with me forever. You are my father, teacher, friend and, most importantly, my hero.