My families consider ____ a computer, which is considered _____ a great help in our work and study.[ ]

A. to buy ; to be  

B. buying ; being  

C. to buy ; being    

D. buying ; to be

药物诱导的血小板减少症（HIT）的诊断金标准是（）。

A.血小板聚集试验

B.血小板抗体检测

C.血小板计数

D.血清素释放试验

E.肝素诱导的血小板源性微颗粒的测定