In order to have better understanding of the accident, the three witnesses were called for second meeting．
A. a; a
B. the; a
C. a; 不填
D. 不填; the
网友回答
(答案→)A. a; a
B. the; a
C. a; 不填
D. 不填; the
解析：have a better understanding of“对…有很好的了解”；序数词前用不定冠词表示“再一次、又一次”不表顺序。所以答案为A。