1. Thrombosis is the formation of a blood clot inside a blood vessel, obstructing the flow of blood.
（血栓形成是指血管内形成血栓，阻塞了血液的流动。）
2. Deep vein thrombosis (DVT) is a serious condition where a blood clot forms in a deep vein, usually in the leg.
（深静脉血栓形成是一种严重的疾病，一般发生在深静脉，通常在腿部形成血栓。）