之前 before; prior to; ago 五年之前 five years ago; 在她动身之前 prior to her departure; 开会之前 before the meeting; 临走之前 prior to departure; before departure; 两周之前 two weeks ago
The failed bombings came just two weeks after coordinated suicide attacks on london ' s transport system killed 52 commuters 在这次爆炸未遂事件的两周之前,恰恰那次针对伦敦交通系统的自杀爆炸事件,有52个受害者在此次事件中丧生。