Measures have been taken to solve the problem, but it may be some time________the situation improves.[ ]

A. since  

B. when  

C. unless  

D. before

对鉴别Ⅱ期Ⅲ期高血压有意义的是（）

A.有无眼底动脉硬化

B.有无左心室肥大

C.有无左心衰竭

D.尿中有无蛋白

E.血压增高的程度