问题补充：
The present system no longer meets the changing needs of our customers; we have to make
a (n) management system.
A. contradictory
B. endless
C. flexible
D. concrete
答案：
A. contradictory
B. endless
(答案→)C. flexible
D. concrete
解析：词义辨析. contradictory矛盾的,反对的;endless连续的,无止境的;flexible灵活的,柔韧的;concrete实在的,具体的.句意：当今的系统不再适合我们的顾客们不断变化的需要．我们必须制定一个灵活的管理制度．结合语境可知选Ｃ．
