Background: Patellofemoral pain syndrome is one of the most common knee problems and may be related to abnormal patellar tracking.

背景知识概要：髌股关节疼痛综合症是最常见的膝关节病变之一，可能和异常的髌骨轨迹有关。

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Background - : An abnormal ECG during maximal exercise testing has been shown to be a powerful predictor of future coronary heart disease (CHD) mortality in asymptomatic men.

背景：极量运动试验时心电图异常是无症状冠心病患者未来冠心病死亡率的强预测因子。

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At last, this article mainly describes one specific aspect of rural society in wartime, namely the background, exhibition and influences of abnormal Fenjia.

最后，文章重点描述了战时农村社会演变的一个具体方面一非正常分家行为发生的背景、表现及影响。

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For somebody with my background and record with respect to coronary artery disease and previous heart attacks, there is that possibility of abnormal heartbeats and about two weeks ago we did a test that's, in effect, an electrocardiogram that you wear for a long period of time.

CNN: Vice President on his latest heart problem