Complex sentence: At a conceptual level, US intelligence knew that al-Qaida actions almost always involve multiple, near-simultaneous attacks; however, the FBI did not assimilate piecemeal information on oddly-behaving foreign flight-training students into this context.
Split into simpler sentences: At a conceptual level, US intelligence knew that al-Qaida actions almost always involve multiple, near-simultaneous attacks. The FBI did not assimilate piecemeal information on oddly-behaving foreign flight-training students into this context.