The police were seeking more information to find out ______ the rich merchant. [ ]

A. who was it that killed

B. who it was that killed

C. it was who killed

D. who was it killed

喉癌根治术后无喉者恢复言语交流最好的方法是（）

A.食管发声的言语训练

B.安装气动式人工喉

C.安装电子式人工喉

D.喉重建手术

E.应用文字图像交流板