What does it mean: 'carried on'? Is it an idiom?

[Lirlik]

Test No. errors/inter-14 "Great expections when you are so carried away", question 9

Dave is so carried on with it all that he's put the baby's name down for a very expensive private boys' school.

(a) on
(b) put
(c) down

Test No. errors/inter-14 "Great expections when you are so carried away", answer 9

Dave is so carried away with it all that he's put the baby's name down for a very expensive private boys' school.

Correct entry: away
The error was: (a) on
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What does it mean?
So carried on

[Torsten]

excited; enthusiastic
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Test Of English for International Communication
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