对于肺炎链球菌引起的肺炎，下列检查最有价值的是（）

A.痰培养为肺炎链球菌

B.血白细胞总数及中性粒细胞数增高

C.肺实变体征

D.X线胸片示肺部大片状阴影，呈肺叶或肺段分布

E.肺部湿性啰音

The operation of which aids to navigation may be suspended during war or national emergency（）.

A.Navigational satellites

B.Loran

C.Omega

D.Any of the above