The latter is extremely rare historically, though not impossible.

第二种做法在历史上是极为罕见的，但也不是不可能。

youdao

For example it's difficult (though not impossible) to argue that the policy is both impotent and inflationary.

BBC: Quantitatively more easing from the Bank

This is arguably hardest in services, though not impossible: even journalists find that work expands to fill available hours.

ECONOMIST: Economics focus

His social liberalism would test PAN voters' loyalty, causing party leaders to say such a deal is unlikely, though not impossible.

ECONOMIST: Mexico's ruling party