I used to stop for hitch-hikers'till the day I picked up that maniac.
自从有一天搭了一个精神病人以后,我碰到搭顺风车的人就不再停下来了。
for fear the agents of other firms should be able to trace the kind of research they are likely to be undertaking.
他们生怕别的公司的情报人员据此摸到他们可能要从事的某项科研项目。