【题目】It was 1897________ a European chemist called Dr. Felix Hoffman produced aspirin from this chemical.
A. that B. while C. when D. in which
在线课程【答案】C
【解析】
试题分析：考查定语从句。句意：那是一位欧洲的名叫Felix Hoffman的博士药剂师从这种药品中制造出阿司匹林的1897年。空后的定语从句缺少时间状语，while不可以引导定语从句；若看作强调句型，则1897前应用介词in。故可知选C项。