我们徒步穿过茂密的森林，几乎看不到天空。

We hiked through the ___thick forest, barely seeing the sky.

他有一头浓密的头发，似乎永远不会变乱。

He has incredibly ___thick hair that never seems to get messy.

小路被茂密的灌木丛和多刺的植物挡住了。

The path was blocked by ___thick bushes and thorny plants.