An underground organisation has claimed responsibility for the bomb explosion...是什么意思？

An underground organisation has claimed responsibility for the bomb explosion...

一个地下组织已经声称对这起炸弹爆炸事件负责。

an

art. 一（在元音字母前代替不定代词a），一任一某一，一个；

例句
He started eating an apple...
他开始吃苹果。

underground

adj. 地下的，秘密的，先锋派的，隐蔽的；

例句
...an extensive network of fortified underground bunkers.
四通八达的地下防御工事

organisation

n. <主英>组织，机构，团体；

例句
His application for membership of the organisation was rejected...
他想要加入该组织的申请遭到了拒绝。

has

v. 有( have的第三人称单数 )，（亲属关系中）接受，拿，买到；

例句
...the operation a patient has had.
病人做过的手术

claimed

v. 要求（应得权利）( claim的过去式和过去分词 )，声称，需要，夺走；

例句
He claimed that his parents had abandoned him...
他声称父母遗弃了他。

responsibility

n. 责任，职责，责任感，责任心，负责任；

例句
Many parents simply abdicate all responsibility for their children.
许多父母对孩子简直是完全撒手不管。

for

prep. 为，为了，倾向于，关于，当作；conj. 因为，由于；

例句
I've come looking for a bit of advice.
我特来讨教。

the

art. 指已提到的人（物），指说话人与听者已知的人（物），用于独一无二的事物前，与形容词最高级和序数词连用；

例句
He did have a real knowledge of the country...
他对该国的确知之甚多。

bomb

n. 炸弹，彻底的失败，[橄榄球] 长传，高压贮罐；vt. 轰炸，投弹于；vi. 投弹，[俚语] 惨败，[俚语] 涂鸦；

例句
She had been trying to assemble the bomb when it went off in her arms...
在她试图组装炸弹时，炸弹在她怀里爆炸了。

explosion

n. 爆炸，炸裂，爆发，扩张，激增，（感情，尤指愤怒的）突然爆发；

例句
They heard a loud explosion and saw a ball of fire go up.
他们听见一声爆炸的巨响，看见一个火球腾空而起。