设备安全装置包括（）A.防护装置 B.保险 C.信号灯 D.危险警告

下列离子方程式书写正确的是

A．Fe(NO₃)₃溶液中加入过量的HI溶液：3Fe^3＋＋2I^－＝3Fe^2＋＋I₂

B．NaNO₂溶液中加入酸性KMnO₄溶液：2MnO₄^－＋5NO₂^－＋6H^＋＝2Mn^2＋＋5NO₃^－＋3H₂O

C．漂白粉溶液中通入过量CO₂气体：Ca²⁺+2ClO^－+CO₂+H₂O=CaCO₃↓+2HClO

D．向NH₄Al（SO₄）₂溶液中不断滴加Ba（OH）₂至溶液中SO₄^2－完全沉淀；2Ba^2－+4OH^－+Al³⁺+2SO₄²=2BaSO₄↓+AlO₂^－+2H₂O

婴儿发音的发展顺序是( )。

A．简单发音阶段，多音节阶段，有意义的语音

B．简单发音阶段，有意义的语音，多音节阶段

C．多音节阶段，有意义的语音，完整句子

D．多音节阶段，有意义的语音，电报句

结胸证的证候特点是（）

A.按之濡

B.按之痛

C.寸脉浮

D.关脉小细沉紧

E.关脉沉

The most popular organic gem is the pearl. A pearl is the response of a marine mollusk to the presence of an irritating impurity accidentally introduced into its body; a cultured pearl is the result of the intentional insertion of a mother-of-pearl bead into a live mollusk. Whether introduced accidentally or intentionally, the pearl-making process is the same: the mollusk coats the irritant with a substance called nacre. Nacre is composed chiefly of calcium carbonate. Because very few natural pearls are now on the market, most pearls used in fine jewelry are cultured. These include "Biwa" pearls and most other freshwater pearls. Cultured pearls are not easily distinguished from natural pearls except by an expert.

The difference between a pearl and a cultured pearl is the nature of the________.

A．color

B．introduction of the irritating impurity

C．coating material

D．irritating impurity

采用直接输入原始凭证由会计核算软件自动生成记账凭证的，在生成正式机内记账凭证前，应当进行审核确认。( )