"The ambiguity that's in those answers is very,very difficult for humans to understand, never mind a computer to understand.

VOA: special.2011.02.28

So,just being able to pick one of those up will help our visitors understand how difficult portability was about thirty years ago."

VOA: special.2011.02.15

It was difficult for her to understand why she had married.

VOA: special.2009.06.27

He hoped he had made the country understand one thing: the great need to forget hatred and bitterness in the difficult time of re-building that would follow the war.

VOA: special.2009.12.31