在石头地上追踪动物很困难。

It's difficult to ___track an animal over stony ground.

军方可以使用雷达卫星来追踪地面部队的移动。

The military can use radar satellites to ___track troop movements on the ground.

丢失的行李被追踪到亚特兰大。

The lost luggage was ___tracked to Atlanta.