I wonder why Jack always gets good marks when he does only ______ the others. [ ]

A. half as much as

B. as much as half

C. half as many as

D. as many as half

化脓性关节炎与关节结核的鉴别，下列哪项无价值

A．是否有高热等急性全身表现

B．局部是否有红肿、疼痛与皮温明显增高

C．血和关节液的白细胞总数和中性粒细胞增多的程度

D．浮髌试验阳性

E．关节液是否培养出革兰氏阳性球菌