Sadly, I was curious, so I went to see just how tricky these questions might be. Then I discovered questions such as,
What is the plural of deer?
It makes me nervous that someone writing for a major online site thought something like this to be a tad on the difficult side, and I'm a little afraid for the US at the moment, because adults having trouble with this type of question would seem to be a major lapse in education. In fact, fifth graders having trouble with this would be a big "uh-oh" sign.