Progress was frustratingly slow.

进展慢得使人沮丧。

《牛津词典》

But the process is frustratingly slow.

但这过程慢得让人郁闷。

youdao

The problem for most people with incremental change is that it’s frustratingly slow.

对于大多数人来说，递增变化的缺陷在于，它慢的让人抓狂。

youdao

Then he had a machine that granted each pigeon one piece of corn every fifteen seconds; that's very, frustratingly slow for a hungry pigeon to get one piece every fifteen seconds.

他们设计了一个能保证,每隔15秒给鸽子喂一玉米粒的装置,对饥饿的鸽子来说是杯水车薪,每15秒才只有一粒玉米

耶鲁公开课 - 金融市场课程节选

The frustratingly slow progress in rebuilding New Orleans has filled newspapers in the run-up to the anniversary.

ECONOMIST: In Katrina's wake

Police initially blamed Shiite pilgrims trying to push past frustratingly slow security checkpoints near the Imam al-Hussein mosque.

NPR: Clashes in Karbala Force Pilgrims to Flee

The whole point of CES is to stand in long, frustratingly slow moving lines to fondle devices that promise unlimited freedom.

CNN: How the Consumer Electronics Show lost its spark