b. John-wa ainugo-no kenkyuu no sai, Mary-wa suwahirigo-no tyoosa no sai, ronbun-o kaita.
John-TOP Ainu-GEN research GEN occasion, Mary-TOP Swahili-GEN survey GEN occasion, paper-ACC wrote
John wrote a paper on the occasion of studying Ainu and Mary did so on the occasion of surveying Swahili.