Matched context for prevent back and impede

The page lists matched contexts for prevent back and impede.

Share - prevent back	Share - impede	Phrase
22.16%	16.89%	{prevent back or impede} flow [perform operation]
7.78%	1.41%	{prevent back or impede} fuel [perform operation]
4.86%	1.19%	substantially [degree] {prevent back or impede}