That doesn't mean that banner ads haven't been lucrative for some publishers who place them on their sites -- but it does call into question how long that sort of advertising will last.

它并不是说广告条对刊登它的广告发布商无利可图，但它不禁让我们怀疑这种广告还能维持多久。

youdao

Such questions bear closely on the question of market integration and call for further inquiry.

这些问题和市场整合问题有着紧密联系，需要更进一步的研究。

youdao

And mixed economic signals continue to call into question how long it will take for the country to emerge from recession.

有好有坏的经济信号继续使人们怀疑美国将需要多长时间来走出经济衰退。

youdao

And mixed economic signals continue to call into question how long it will take for the country to emerge from recession.

VOA: standard.2010.01.06

"They do not represent official positions or policy, and they do not,in my view, fundamentally call into question the efficacy of our current strategy in Afghanistan and its prospects for success."

VOA: standard.2010.07.30

Ms. SIMON: Martin, thank you for your call and for that question.

NPR: Carly Simon's 'Never Been Gone'

However, in the US the call for more stimuli begs the question of who will buy all the debt that will fund such programmes?

FORBES: Simply Got to Grow, Simply Got to Work

Technology also will call into question the need for the 3, 600 campuses currently in existence in the U.S., as students take advantage of online offerings that are accessible from any location.

CNN: Web brings radical changes to higher education