Matched context for backflow and expulsion

The page lists matched contexts for backflow and expulsion.

Share - backflow	Share - expulsion	Phrase
22.00%	13.56%	prevent {backflow or expulsion} [perform operation]
6.36%	16.16%	fuel {backflow or expulsion}
4.28%	9.03%	gas {backflow or expulsion}
3.20%	10.38%	fluid {backflow or expulsion}
0.75%	7.37%	cause {backflow or expulsion} [perform operation]
1.08%	3.43%	air {backflow or expulsion}