44 years ago, I sent two fresh accounting graduates to observe inventories from our Chicago area home office, one in Seattle and the other in Los Angeles. When they compared plane tickets and realized that the flight times were similar, they had to get out a map to realize where the cities were.
It was quite a surprise for both of them. I have not been surprised about people's lack of knowledge about the world around them since then. Somewhat disappointed, but no longer surprised.
Quiz them on these four basic parts of speech and see how they do.
Noun, verb, adjective, adverb.