In face of failure it is the most important to keep up good state of mind.A. a; 不填B. 不填;

问题补充：

In face of failure, it is the most important to keep up good state of mind.

A. a; 不填

B. 不填; a

C. the; 不填

D. 不填; the

答案：

A. a; 不填

(答案→)B. 不填; a

C. the; 不填

D. 不填; the

解析：考查冠词。failure失败，是不可数名词，前面不用冠词；当指“失败的事或人”时，是可数名词，排除A、C；a good state of mind一种良好的心态，表示泛指，用不定冠词a。故选B。