31.   But the key to the system, and the biggest technological hurdle, is the flywheel.

32.   But the system that was likely to have been the biggest hurdle to getting Discovery cleared for launch was a high-pressure pocket that seemed not to be moving Monday.

33.   But the biggest hurdle is not teaching poor people.

34.   Congress may be the biggest hurdle to opening more combat jobs to women.

35.   Coleman said the biggest hurdle is the lack of information to voters.

36.   Critics say the biggest legal hurdles to winning any court judgments are the passage of time and the fact that direct victims of slavery are long dead.

37.   Finding space may be your biggest hurdle.

38.   For Bush, it was a solid day that began with him noting that among his biggest hurdles has been high expectations.

39.   For now, its biggest hurdle is its location.

40.   For now, the biggest hurdle is working with variables of human behavior.