“Design of experiments” is a statistical method that helps ______ .

A) determine how various elements of a system interrelate
B) identify which factors may influence specific variables of a product or process
C) establish a standard by which to measure performance
D) compare actual or planned project practices to those of other projects

牛黄、熊胆都具有的功效是

A．开窍

B．化痰

C．明目

D．利咽

E．止痉