but then (again)

after all; on the other hand (introducing a contrasting comment)

另一方面，然而

it couldn't help, but then again, it probably couldn't hurt.

它沒什么用，不過可能也沒危害。

then and there

immediately

當場，立即

and then some【非正式用語】

With considerably more in addition

而且遠不止此

This project will take all our skill and then some.

這個工程將采用我們所有的技術，而且遠不止此