这项研究追踪了1226名在密歇根大学医学院接受培训的医生的职业生涯。

The study ___tracked the careers of 1226 doctors who trained at the University of Michigan Medical School.

然而，追踪战争的爆发并因此评判人类不吸取教训是徒劳的。

However, it would be useless to ___track the outbreak of wars and to judge humanity for not learning.

研究人员追踪鸟类多年的迁徙模式以理解气候变化的影响。

Researchers ___track the migration patterns of birds over several years to understand climate change effects.