The problem would be repeated ad infinitum.

这个问题会一再出现。

《牛津词典》

The meetings will be held on an ad hoc basis.

会议将根据需要随时举行。

《牛津词典》

The time you spend on an ad hoc project tends to be fairly short.

你花在一个特别项目上的时间往往是相当短的。

youdao

"There has to be a strategy beyond just a 30-second ad.

VOA: standard.2010.01.27

You remember he's written his father in "Ad Patrem" that the trade, the vocation of poetry -- it may be homely and slighted in his father's eyes, but it was of course worth all of Milton's time, all of Milton's uncessant care and investment.

他在写给父亲的Ad，Patrem中说，写诗这个职业在父亲看来或许,简单无趣，却值得弥尔顿付出所有的时间，精力，和投资。

耶鲁公开课 - 弥尔顿课程节选

These sit just above a small Special Offers banner ad -- always be selling, Amazon, coffee is for closers.

ENGADGET: Amazon Kindle Paperwhite review

The drawings - believed to have been made between 700 BC and 900 AD - can only be fully seen from the air.

BBC: News | Americas | Lady of the lines

Another major ad-buying company suggested that ad sales could be flat at broadcast networks and higher at cable networks.

WSJ: Signals Weak for TV-Ad Market