他无情的野心驱使他背叛了自己最亲密的盟友。

His ___ruthless ambition led him to betray his closest allies.

那位冷酷无情的独裁者以铁腕手段镇压了一切反对派。

The ___ruthless dictator suppressed all opposition with an iron fist.

在当今的商界，竞争可能是极其残酷无情的。

In today's business world, the competition can be absolutely ___ruthless.