将下列气体通入水中，其饱和水溶液酸性最强的是 A．CH4 B．NH3 C．HBr

梅龙高速公路是广东梅州至福建龙岩高速公路，总投资59.57亿元。那么数据5 957 000 000用科学记数法表示是       .

-Mrs. Smith never thought his son could make such great progress, ______?

-______, because he had never got such good scores before.[ ]

A. could she; Yes, he could

B. did she; Yes, she did

C. couldn't she; No, he couldn't

D. did she; No, she didn't

根管消毒药应具备的条件如下，除外（）。

A.不使牙齿染色

B.渗透性强

C.杀菌力强

D.性能稳定

E.刺激根尖周组织

咬定青山不放松，立根原在破岩中。千磨万击还坚劲，任尔东西南北风。——《竹石》

这是一首咏物诗，我们从中应感悟到中华儿女应有怎样的民族精神？

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治疗瘴疟宜选（）

A.柴胡截疟饮

B.清瘴汤

C.加味不换金正气散

D.何人饮

E.白虎加桂枝汤