随着友谊的发展，他们之间的信任加深了。

As their friendship grew, the trust between them ___deepened.

他们挖深了花园里的池塘，以便养更多的鱼。

They ___deepened the pond in the garden to keep more fish.

随着夜色降临，树林的颜色逐渐加深。

The color of the forest ___deepens as night falls.