Matched context for obstruction and contamination

The page lists matched contexts for obstruction and contamination.

Share - obstruction	Share - contamination	Phrase
6.56%	2.43%	free of {obstruction or contamination}
0.92%	7.99%	prevent {obstruction or contamination} [perform operation]
3.34%	1.81%	avoid {obstruction or contamination} [perform operation]
1.99%	2.03%	minimize {obstruction or contamination} [perform operation]
1.55%	1.87%	remove {obstruction or contamination} [perform operation]
1.10%	0.81%	cause {obstruction or contamination} [perform operation]
1.15%	0.54%	not {obstruction or contamination}