You can be in deep water, for example, if you invest in stocks without knowing anything about the stock market.

VOA: special.2009.05.10

Knowing more about how the Yarkovsky effect changes an asteroid's orbit will help scientists better predict whether RQ36 will come near Earth.

VOA: special.2011.06.22

writer Dava Sobel tells the story about longitude and how the problem of knowing it was solved.

VOA: special.2010.07.14

"When I was talking about knowing if my business is viable or not, through a profit-and-loss model, I was like 'Wow,I didn't even know the word viable before, and now I do.'

VOA: special.2011.06.30