They've arrogated to themselves the power to change the rules arbitrarily.他们僭取权力，肆意改变规定。The number was arbitrarily chosen.数字是任选的。People did not accept these national borders which had been arbitrarily imposed.民众不接受这些以蛮横方式强行划定的国界。The victims were not chosen arbitrarily.下手对象不是随便选择的。