Blade is part of Knife. Knife is related to Operation. Operation is a type of Activity. Activity is related to Business. 
Difference is related to Comparison. Comparison is a type of Examination. Examination is related to Office. 
Blade --PartOf--> Knife <--RelatedTo--> Operation --IsA--> Activity <--RelatedTo--> Business 
Difference <--RelatedTo--> Comparison --IsA--> Examination <--RelatedTo--> Office 