语法与词汇 The two scholars worked at the task of writing a preface to the new dictionary for three hours _____ last night.无
【正确答案】 C
【答案解析】句意: 那两位学者昨天晚上花了三个小时为新字典写序。 on end连续不断地。 at length最后, 终于。in full全部地。 in time及时。