病历摘要：青年男性，突然出现高热衰竭、出血症状。

下列哪项表现最有助于急性白血病的诊断（）。

A.肝脾肿大

B.皮肤结节

C.头痛、呕吐

D.胸骨下段压痛

E.齿龈肿胀

—________did your uncle leave his hometown?

—He ________ for nearly twenty years.

A．When; has left

B．When; has been away

C．How long; has left

D．How long; has been away