"If you don't understand where you are, it's hard to tell where you are going, " says Steve Blank, professor of entrepreneurship at University of California, Berkeley, and an investor in Startup Compass.

WSJ: Learning How Your Start-Up Stacks Up

When you meet her now, it's hard now to tell anything was ever wrong with T-Boz.

CNN: T-Boz brings reality to TV

It's hard to tell if they themselves are or aren't religious.

CNN: The world's most beautiful places to pray

You don't have to tell him it's time to play and he has to play hard, " said former Devils goaltender Kevin Weekes, who was Parise's teammate in New Jersey and now covers the league for the NHL Network and "Hockey Night in Canada.

WSJ: Will Parise Cross the River?

There are some moments that stay in our minds forever, and sometimes it's hard to tell which things will surface to the top and which ones won't.

NPR: Watching a Memory Shift over Time

We couldn't afford to tell those kids on the West Side or the South Side, if you work hard, if you study hard, if you're hitting the books, that you're going to be able to afford to go to college.

WHITEHOUSE: Remarks by the President at a DNC Event