She couldn't pin him down to a date.

她未能迫使他确定下日期。

《柯林斯英汉双解大词典》

I need the up-to-date sales figures but I can never pin him down at the office.

我需要最新的销售数字，可就是不能在办公室找到他问清楚。

《牛津词典》

The cause of the disease is difficult to pin down precisely.

病因目前还难以解释清楚。

《牛津词典》

"It is very difficult to really pin down and there have been these sorts of accusations from the Revolutionary Guards in the past."

VOA: standard.2009.10.18

That's a quite difficult argument to pin down does it work or does it not work.

这个论证很难确定,是不是说得通。

耶鲁公开课 - 死亡课程节选

You need to pin down an object of study, a first principle from which other principles can emerge, and part of the process is to say, "Hey, it's not literature we're talking about.

首要原则是，需要锁定要谈论，即学习的目标，可是，谁知道什么是文学。

耶鲁公开课 - 文学理论导论课程节选

The stylized action game is actually hard to pin down to a single genre.

FORBES: Connect

Both incidents were terrifying but really hard to pin down a trigger to.

BBC: Children with allergies 'being let down': Your comments

Woodson was still in the process of trying to pin down precisely how to counter the Pacers' top-ranked defense, which appears to have engendered a bit of infighting among the baffled Knick offense.

WSJ: Sometimes Home Isn't Sweet