代谢性碱中毒()A．HCO3-正常 pH↓ +PaCO2↑ B．HCO3-正常 pH

正实数a的两个平方根的立方和是______．

患者，男，11岁。左上1牙颈部冠折，已行根管治疗。

该患者拟采用全冠修复，修复方法为（）

A.铸造桩核+普通金属烤瓷冠

B.铸造桩核+树脂甲冠

C.铸造桩核+全瓷冠

D.铸造桩核+贵金属烤瓷冠

E.成品桩简单桩冠

When is the t- distribution the appropriate distribution to use The t -distribution is the appropriate distribution to use when constructing confidence intervals based on:（）

A. small samples from populations with known variance that are at least approximately normal.

B. large samples from populations with known variance that are nonnormal.

C. small samples from populations with unknown variance that are at least approximately normal.

开关设备机构箱、汇控箱内应有完善的驱潮防潮装置，防止凝露造成二次设备损坏。（）

263用户白天的上网费比2911用户白天的上网费贵多少（）

A．127％

B．44％

C．93％

D．105％