(Gunfire breaks) can be sustained.Logical formLearned from2 sentences. A (border fighting) can be sustained.Logical formLearned from2 sentences. Counter-attacks can be sustained.Logical formLearned from2 sentences. (Artillery exchanges) can be sustained.Logical formLearned from2 sentences. A (poll lead) can be sustained.Logical formLearned from2 sentences. A (diplomatic pressure) can be sustained.Logical formLearned from2 sentences. A (system performance) can be sustained.Logical formLearned from2 sentences. A shelling can be sustained.Logical formLearned from2 sentences. A credit-easing can be sustained.Logical formLearned from1 sentences. A (trade deficit) may undergo a sustained narrowing.Logical formLearned from1 sentences. A (debt reduction) can be sustained.Logical formLearned from1 sentences. A filibuster can be sustained.Logical formLearned from1 sentences. A (floor debate) can be sustained.Logical formLearned from1 sentences. A gasp can be sustained.Logical formLearned from1 sentences. (Synthesizer notes) can be sustained.Logical formLearned from1 sentences.