确定蛋白质标准溶液浓度的最经典方法是( )
A．凯氏定氮法B．双缩脲法C．酚试剂法D．紫外分光光度法E．溴甲酚绿
参考答案：A
Airplanes that used to take more than half a day to cross the Atlantic are now _____ to make it in
several hours.[ ]
A. faster than
B. fast enough
C. so fast
D. faster
设平衡的二叉排序树(AVL树) 的结点个数为n，则其平均检索长度为
A) O(1) B) O(log2n) C) O(n) D) O(nlog2n)
