GRE Text Completion: Fundamental 24 Sets-GRE填空基础24套 - L0U0BM0P088Y6E00!

Ellen Swallow Richards, a (i)____________ environmental preservation in the United States, campaigned during the nineteenth century to (ii)____________ responsible practices in the discipline that has come to be known as ecology. A. foil for B. expose C. pioneer of D. implement E. mitigator of F. squelch