There is reason to believe that most writers have difficulty in ______ the opening paragraphs of their papers.

A．constituting

B．constructing

C．comprising

D．founding

女性，8岁，因贫血、脾大入院。检验：HGB90g／L，WBC8．8×10⁹／L，PLT130×10⁹／L，HGBA2>5．0％，Coombs试验阴性，血片可见少量靶形细胞，红细胞呈小细胞低色素

明确诊断需做的检查是（）

A.血红蛋白电泳

B.腹部超声

C.免疫蛋白电泳

D.Coombs试验

E.骨髓检查