问题补充:
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
答案:
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。