_________the goods,we discovered that they were inferior in qual

_________the goods,we discovered that they were inferior in quality to the sample.
A、After exam
B、Upon examination
C、Examination
D、On examining
【正确答案】：D
【题目解析】：[解析]句意：一检查货物，我们就发现这批货物的质量比样品质量差。on/upon +动名词+名词或on/ upon +名词时意为“一就”；故本题选D