计算机系统软件包括操作系统、语言处理程序、数据库管理系统和______。

将右边的疾病与相应的病因用线段连接起来。

（1）血液中红细胞数目过少或血红蛋白过少            a.糖尿病

（2）血液中白细胞数目显著增加                      b.夜盲症

（3）人体内缺少维生素A                            c.贫血病

（4）成年人胰岛分泌的胰岛素过少                   d.发炎症

油罐为什么要定期检尺？

Passage 2

What is this talk mainly about a. The importance of preventive actions against medical risks b. Americans’ misunderstanding of preventive actions against medical risks. c. The reasons why some Americans fail to react against some medical risks. d. An investigation about Americans’ attitudes toward medical risks and some suggestions.

对于反应C₂H₄(g)→C₂H₂(g)十H₂(g)，2CH₄(g)→C₂H₄(g)+2H₂(g)当升高温度时都向右移动①C(s)+2H₂(g)→CH₄(g)；△H₁ ②2C(s)+ H₂(g)→C₂H₂(g)；△H₂  ③2C(s)+2H₂(g)→C₂H₄ (g)；△H₃。判定①②③中的△H₁，△H₂，△H₃大小顺序是                                  （   ）

A．△H₁>△H₂>△H₃

B．△H₂>△H₃>2△H₁

C．△H₂>△H₁>△H₃

D．△H₃>△H₂>2△H_l

混凝土结构工程施工时，对水泥进场质量应如何检查？