Subject	aluminium
Predicate	be expensive to
Object	extract
Modality	Modality Occurrences
Polarity	POSITIVE
Plausibility	0.9507
Neighborhood Sigma	0.9508
Local Sigma	1.0000
Example Sentences	Sentence Occurrences Source aluminium is expensive to extract 2 Google Autocomplete aluminium and titanium is expensive to extract 2 Google Autocomplete aluminium and titanium are expensive to extract 2 Answers.com Questions