Here ’ s an article adapted from The Economist . Please try to put it in right order. _______, _______, _______, _______, _______, ________, ________ A. The attacks seemed highly organised, suggesting the shooter or shooters may have been working as part of a bigger cell ( 团伙 ) . One of the terrorists has been confirmed as a man from Australia. B. T errorists attacked two mosques in the city of Christchurch on March 15th, as worshippers were gathering for Friday prayers. At least 49 people, among them children, were killed. C. The gunman went on to broadcast gruesome ( 恐怖的,令人生厌的 ) live footage of his attack on one of the mosques on Facebook. D. The attack raises concerns about the role of social-media companies in enabling extremists to advertise acts of violence. E. Directly before the attack, he uploaded a 73-page manifesto ( 宣言 ) to Twitter. In it he said he was waging war to prevent "white genocide ( 种族灭绝 ) ", a term often used by white nationalists who believe that non-white immigrants are plot ting ( 密谋 ) to "replace" them. F. It is still unclear how many shooters were involved, but police say three suspects have so far been arrested. G. The event casts a cloud, too, over New Zealand's security services. None of those arrested was on a police watchlist ( 警方的重点监察对象 ) .