Mr. Smith ______ a grammar book meant for senior high school students and will almost finish it.

A．has been writing

B．has written

C．was writing

D．has been written

男，18岁，全身水肿、尿少半月。查：血压110/70mmHg，尿蛋白++++，尿RBC0～1个/HP，尿WBCO～2个/HP，Hb130g/L，WBC4.5×10/L，N62%，BUN6.5mmol/L。

为明确诊断，下列哪项检查最有价值()

A．血肌酐

B．血K、Na、Cl测定

C．二氧化碳结合力测定

D．血脂测定

E．血清Tp与ALB