单项选择题
A. 51 pounds B. 1.45 pounds C. 2.42 pounds D. 1.35 pounds E. 16 pounds F. 1.85 pounds G. 17 pounds H. 2.16 pounds
A．in order to be able to tell people what to do. B．because their environment is always changing. C．to enable them to be flexible. D．to help their bosses make decisions.
A．difference B．differences C．difficult D．difficulty