他们徒步穿越沙漠，进行了一次艰难的长途跋涉。

They ___trekked across the desert on a challenging long-distance journey.

我们的山地徒步旅行持续了整整一周。

Our mountain ___trek lasted for a whole week.

我们不得不背着沉重的背包缓慢徒步穿过崎岖的山路。

We had to ___trek slowly with heavy backpacks through the rugged mountain trail.