单选题 The researchers are working with food companies keen to see if their products can be made resistant to bacterial attack through alterations ______ the food's structure.
A. for B. of
C. to D. in

【正确答案】 C

【答案解析】alteration要求接介词to，意为“对……的改变”，故只有C正确。另外形容词短语keen to see if their products can be made resistant to bacterial attack through alterations to the food's structure作后置定语，修饰food companies。句意为：“研究人员在和食品公司一起从事研究工作，这些公司热衷于搞清楚是否能通过改变食品结构使得他们的产品经得住细菌的侵袭。”