dense

It was difficult to see through the dense fog that covered the highway early this morning.

(Chinese) 很难看穿今天清晨覆盖高速公路的浓雾。

The explorers struggled to move through the dense jungle vegetation.

(Chinese) 探险家们艰难地穿行在密集的丛林植被中。

He must be a bit dense if he still hasn't realized that she is joking.

(Chinese) 如果他还没意识到她在开玩笑，那他肯定有点反应迟钝。

I'm sorry if I'm being dense, but could you explain that complex math problem one more time?

(Chinese) 如果我显得有点笨请见谅，但你能再解释一遍那个复杂的数学题吗？