小儿各系统器官发育最早的是（）。 A.神经系统 B.骨骼系统 C.淋巴系统 D.生殖

The purpose of (66) is to enlarge the (67) , the set of addresses a program can utilize. For example, it might contain twice as many addresses as main memory. A program using all of it, therefore, would not be able to fit in main memory all at once. Nevertheless, the computer could execute such a program by Copying into main memory those portions of the program needed at any given point during execution.
To facilitate copying (66) into real memory, the operating system divides it into pages, each of which contains a fixed number of addresses. Each page is stored on a disk until ii is needed. When the page is needed, the operating system copies it from disk to main memory, translating the (68) into real addresses. The process of translating virtual addresses into real addresses is called (69) . The copying of virtual pages from disk to main memory is known as (70) or swapping.

A．drawing

B．mapping

C．picturing

D．scanning

元素周期表中，钙元素和镁元素同在一个纵行里，它们的原子结构示意图如图所示，则：

（1）钙与镁的化学性质______（填“相似”、“相同”或“不同“），理由是______．

（2）钙元素的核电荷数为______；在元素周期表中属第______周期；钙离子的化学符号为______；钙离子与镁原子的不同在于______．

如图所示装置测定种子萌发时进行的细胞呼吸类型。同时关闭活塞，在25℃下经过20min再观察红色液滴的移动情况，下列对实验结果的分析不符合实际的是

A．装置1的红色液滴向左移动的体积是细胞呼吸消耗O₂的体积，装置2的红色液滴向右移动的体积是细胞呼吸释放CO₂和消耗O₂的体积之差

B．若装置1的红色液滴左移，装置2的红色液滴不移动，则说明萌发的种子既进行有氧呼吸也进行无氧呼吸

C．若装置1的红色液滴左移，装置2的红色液滴右移，则说明萌发的种子既进行有氧呼吸又进行无氧呼吸

D．若装置1的红色液滴不移动，装置2的红色液滴右移，则说明萌发的种子只进行无氧呼吸

反乌头的中药是（）

A.瓜蒌

B.贝母

C.知母

D.夏枯草

E.半夏

中国邮政储蓄银行案件防控领导小组会议原则上（）召开一次。

A.每年

B.每季度

C.每月

D.每周