wE lEArn From thE pAssAgE thAt olEstrA is A suBstAnCE thAt______.
A．ContAins plEnty oF nutriEnts
B．rEnDErs FooDs CAloriE-FrEE whilE rEtAining thEir vitAmins
C．mAkEs FooDs EAsily DigEstiBlE
D．mAkEs FooDs FAt FrEE whilE kEEping thEm DEliCious