The sky darkled at the approaching storm.

风暴临前天空下。

The night darkles rapidly.

夜很快地黑下。

The precipice darkles in front.

山崖的前面是阴的。

If the silvered jewelry do not keep in a sealed environment or wipe it oftenly, it will caused the the color and luster become darkle.

未密封保存或经常擦拭，易使色泽变。