6. While two detectives were keeping guard at the door, two others opened the parcel.
两名侦探正在门口警戒，另外两名则把这个包裹打开。
7. In production the workers made full use of the old equipment.
这些工人在生产上充分地利用这个旧设备。
8. Although he reached a speed of over 304 miles per hour, Campbell had great difficulty in controlling the car because a tyre burst during the first run.
虽然坎贝尔达到304英里以上的时速，但他很难控制住这辆汽车，因为在头一段路上就已有一只车胎爆裂了。
〔解说〕本例句中介词in后的宾语controlling the car按原有的语法直译成“在（控制住这辆汽车）方 面”的状语形式，置于谓语动词的前面，当然是可以的。采用哪种译法较合运，这应由译文的上下句意思的连贯和文句的衔接来决定。