Question

john had made up his mind to give it up,but on_second thought he determined to try_third time.

a./ a b./ / c.a a d.the a

Answer 1

a./ a
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
约翰本来打定主意放弃了，但转念一想，又决定再试一次