Tom had made up his mind to give it up, but on second thought he determined to have third try.
A. a ; a
B. 不填 ; a
C. 不填; 不填
D. the ; a
网友回答
A. a ; a
(答案→)B. 不填 ; a
C. 不填; 不填
D. the ; a
解析：本题考查冠词。on second thought固定结构，转念一想;a third time,又/再一次，无论序数词是几，都加a/an，句意：约翰本来打定主意放弃了，但转念一想，又决定再试一次。