At will：随意，任意
12月19日，伊拉克圣城纳杰夫和卡尔巴拉分别发生两起汽车炸弹袭击事件，共造成60多人死亡，130余人受伤。外电报道如下：Car bombs tore through a Najaf funeral procession and Karbala's main bus station Sunday, killing at least 60 people and wounding more than 120 in the two Shiite holy cities. In Baghdad, gunmen launched a bold ambush, executing three election officials, in their campaign to disrupt next month's parliamentary ballot.
The deadly strikes highlighted the apparent ability of the insurgents to launch attacks almost at will, despite confident assessments by U.S. military commanders that they had regained the initiative after last month's campaign against militants in Fallujah.
In the Baghdad attack, dozens of guerrillas - unmasked and apparently unafraid to show their faces - ran rampant over Haifa Street, a main downtown thoroughfare. They dragged the three election workers from a car, lay them on the street in the middle of morning traffic and shot them point-blank.
At will表示“随意，任意地，恰在希望的时候”，例如：the ability to go anywhere at will and to transform oneself or any object at will（随心所欲地到达任何地方、改变自身或任何物体的能力）。