由十六烷基吡啶翁改变为十四酰氧甲基吡啶锚所采用的原理是（）.A．前药原理 B．定量构
题型：单项选择题
问题：
由十六烷基吡啶翁改变为十四酰氧甲基吡啶锚所采用的原理是（）.
A．前药原理
B．定量构效关系
C．研究体内代谢
D．生物电子等排原理
E．软药原理
题型：单项选择题
The World’s Most Impressive subways
小题1:Which of the following gives the passengers the best visual enjoyment?
A．The Tokyo Metro and Toei Lines．
B．The Moscow Metro．
C．The London Metro．
D．The Hong Kong MTR．小题2:According to the passage, the only subway that can bring more financial gains is ______．
A．the Tokyo Metro and Toei Lines
B．the Moscow Metro
C．the London Metro
D．the Hong Kong MTR小题3:We can learn from the passage that Shanghai Metro ______．
A．is the busiest system in the world
B．carries the most people each day
C．may be larger than the Chicago Subway in the future
D．has become the world's largest subway since it opened小题4:The purpose of the passage is to _____．
A．give us a brief introduction to some subway systems
B．introduce the working system of some railways station
C．tell the general background of world-wide transportation
D．show the historical development of underground system