关于急性肢体动脉栓塞，下列说法正确的是（）

A.突发肢体肿胀

B.病人常伴有高血压

C.通常可以采用溶栓药物进行非手术治疗

D.患肢冰冷，发绀

E.肢体已出现坏死平面，需立即手术取栓

At the railway station, the mother waved goodbye to her daughter until the train was _______.

A．out of sight

B．out of reach

C．out of order

D．out of place