这位君主毫不留情地把他的意志强加于人民。 The Prince would work his will on the people without mercy.
他过去毫不留情地欺侮他的秘书，但是如被逼太甚，最温顺者也会反抗的，结果有一天她不辞而别了。 He used to bully his secretary without mercy, but even a worm will turn and one day she walked out and left her job without even saying goodbye.
敌人冲破了前线，但被我们的骑兵部队毫不留情地从高地击退。 The enemy broke through the front line, but were firmly repulsed from the higher ground by cavalry.