单选题
英语运用能力测试
2011-10-22
Commercial application of the research finding will be possible if salad cream can be made resistant to bacterial attack__________
A．by varying its chemical composition
B．by turning it into a solid lump
C．while keeping its structure unchanged
D．while retaining its liquid form
参考答案
D
答案解析
依据是最后一段相关内容，注意：该句中的while是时间概念，相当于in the course of。
