1·They were surveyed about their diets during high school and their eating habits were tracked for two decades.
该研究调查了她们高中时期的日常饮食，并跟踪她们的饮食习惯长达二十年。
2·In the past couple of weeks a quarrel has illustrated the value to advertisers of such fine-grained information: Should advertisers assume that people are happy to be tracked and sent behavioural ads?
在过去几周里，一场争论说明了这种精细的信息对于广告商的价值：广告商是否可以认为用户愿意被跟踪并投放行为广告？
3·Even in the worst case, when a change record starts off as vague or high-level, it is at least being tracked and documented.
即使在最糟糕的情况下，当一个变更记录以模糊的状态或者高层次开始时，它至少要被跟踪和存档。
4·Changes are tracked by file instead of per change, which can be annoying.
变更可以按文件跟踪，而非按变更本身，这点十分讨厌。
5·For this reason, changes to their reference set must be tracked, as we discussed in Write barriers.
出于这个原因，必须跟踪对它们的引用设置的更改，如写入屏障一节所述。