Unhappy is a synonym of Sorry. Sorry is related to Cry. Cry is related to Action. Action is related to Cook. 
Tighten is a type of Change. Strain is a type of Tighten. Strain is a type of Disease. Disease is related to Medicine. 
Unhappy <--Synonym--> Sorry <--RelatedTo--> Cry <--RelatedTo--> Action <--RelatedTo--> Cook 
Change <--IsA-- Tighten <--IsA-- Strain --IsA--> Disease <--RelatedTo--> Medicine 