单选题 In ______, the experiment was more difficult than we had imagined.

【正确答案】 B
【答案解析】in retrospect回顾(主要指回首过去的事)；response回答：in response to your inquiry答复你的咨询；consequence(某事的)后果，影响：in consequence (of)结果，因而；particular特殊的：in particular特别地，尤其。