She lay in her bed and had the feeling_______ nothing  would make her sleep.       [ ]

A. what    

B. which    

C. of which  

D . that

离子选择电极法测定K+时所用的电极属（ ）

A．玻璃膜电极

B．固相膜电极

C．液态膜电极

D．甘汞电极

E．缬氨霉素膜电极