— Why did you stop writing?

— My ink has________.[ ]

A. been run out  

B. used up

C. been used out  

D. given out

表面活性剂分子中两种基团的亲水性和亲油性的强弱的平衡值称

A．CRH

B．Krafft 点

C．CMC

D．昙点

E．HLB 值