The boys' attack on the old woman was quite unprovoked.
那帮男孩对老妇人的袭击完全是无来由的。
I ask that the Congress declare that since the unprovoked and dastardly attack by Japan on Sunday December7,1941, a state of war has existed between the United States and the Japanese Empire.
我要求国会宣布：由于日本在1941年12月7日星期日对我国无故进行卑鄙的袭击, 美国同日本已经处于战争状态。
An unprovoked attack.
未经挑衅就发动的进攻
