But then again e But there again

Avatar do usuário Marcio_Farias 12440 1 22 210
O livro "English Guides 9: Linking Words", da Collins Cobuild, traz as duas variantes, mas eu gostaria de saber qual delas é britânica e americana.

O livro diz:

"You can use then again or there again to signal that you are about to add some new idea or fact that is rather different from what you or someone else has been saying, so you can use them to introduce an opposing argument. Both expressions are used in writing, but are particularly heard in speech. The meaning is roughly the same as 'on the other hand'."
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Avatar do usuário PPAULO 42595 6 33 751
None of them. If we are to go by Oxford Dictionary´s entry "again".
I made a search into The Guardian/BBC (British) and PBS, and then I crawled within Newsweek magazine.

The only remarks I would make is that "but then again" is found (slightly) more often, and that Newsweek didn´t use "but there again", but the other way, if I got it well (in a quick passing glance, I mean).

"but then", "then again" (and others) would replace both, in a more lay and informal terms.

In the Cambridge Dictionary they register just the "but then again", maybe it suggests that "but there again" is a corruption (corruptela) of it? I wonder...

the keywords to type on Google -

"but then again" "but there again" site:www.pbs.org/
"but then again" 'but there again" site:www.newsweek.com/
Avatar do usuário Henry Cunha 10000 3 16 177
I happen to like the Collins Cobuild a lot, and know that it is based on both British and American English usage, so I would have no reason to believe that either of these expressions is more British or more American. (See the section "a corpus-based dictionary" in the review at http://www.antimoon.com/how/cobuild-review.htm.)

I agree with Paulo that "then again" is probably much more frequent. But there may be instances where (when?) "there again" may be preferred because of a reference to an identified physical state, situation or place.