【题目】过了近两个小时，Tom才把作业做完。
It took nearly two hours .

【答案】efore Tom finished his homework
【解析】 句型“it was +时间段+ before …” 表示 “过了（多长时间）才……”。结合前文took可知时态为一般过去时，所以答案是before Tom finished his homework.