Officials may investigate a cause of explosions.Logical formLearned from8 sentences. An explosion may kill a ringleader of (train bombings).Logical formLearned from8 sentences. An explosion may send_up a plume of black smoke.Logical formLearned from8 sentences. Explosions may be heard in a neighborhood.Logical formLearned from8 sentences. Envoys may visit a site of an explosion a weekend.Logical formLearned from8 sentences. A (train explosion) can be in a country.Logical formLearned from8 sentences. An explosion can be at a (railway station).Logical formLearned from8 sentences. Some helicopters may rove over a site of an explosion.Logical formLearned from8 sentences. An explosion may tear through a structure.Logical formLearned from8 sentences. An explosion may be blamed on a natural-gas leak.Logical formLearned from8 sentences. A source of an explosion may be knowned.Logical formLearned from8 sentences. An explosion can be at a (soccer stadium).Logical formLearned from8 sentences. Explosions can be in (apartment buildings).Logical formLearned from8 sentences. A (test flight) may end in an explosion.Logical formLearned from8 sentences. Persons may be killed in some days of explosions.Logical formLearned from8 sentences.