达尔文认为生物生存斗争的主要原因是：A．遗传和变异B．适者生存C．过度繁殖D．捕食
有关真核细胞DNA复制和转录这两种过程的叙述，错误的是 A．复制和转录过程中都会发生DNA分子的解旋 B．两种过程都有酶参与反应 C．两种过程都以脱
Mr Reed made up his mind to devote all he had to________some schools for poor children. A．set up B．setting up C．have set up D．having set up
将100g溶质质量分数为16%的HCl溶液与100g溶质质量分数为16%的NaOH溶液混合后，滴入几滴紫色石蕊试液，则最终溶液颜色是（）。A.蓝色 B.紫色 C.红色 D.无
（12分）写出下列反应的离子方程式（1）过氧化钠与水 （2）金属铝与稀硫酸溶液
The plane flew smoothly ______ in the sky and people spoke ______ of the experienced pilot. A. high；high B. highly；highly C. high；highly D. highly；high
What actually ______ the accident has not yet been determined. A. brought out B. brought on C. brought about D. brought up
在实验条件下，测试某种变温动物离体细胞的呼吸强度（E）受温度变化的影响，正确结果是（ ）
