医疗队在抗疫前线日夜奋战。

The medical team is working day and night on the ___front line of the epidemic fight.

教师们在教育前线辛勤工作，塑造着下一代的未来。

Teachers working on the ___front line of education shape the future of the next generation.

这家医院在新冠肺炎治疗研究中处于前沿。

This hospital is at the ___front line of COVID-19 treatment research.