（5分）如图是某同学设计的放热反应的观察装置。

其实验顺序是：①按图所示将实验装置连接好。

②在U形管内加入少量红墨水（或品红）溶液。打开T型管螺旋夹，使U形管内两边的液面处于同一水平面，再夹紧螺旋夹。

③在中间的试管里盛1 g氧化钙，当滴入2 mL左右的蒸馏水后，同时打开螺旋夹即可观察。

试回答：

（1）实验中观察到的现象是                                              。

（2）该实验中在安装好装置后必须进行的第一步实验操作是                  。

（3）实验中反应的化学反应方程式是                                      。

（4）说明CaO、H₂O的能量之和      Ca(OH)₂的能量。（填“＞”、“＜”或“＝”）

（5）若该实验中CaO换成NaCl，实验还能否观察到相同现象？        。

One of the most widely used routing protocols in IP networks is the Routing Information Protocol (RIP)．RIP is the canonical example of a routing protocol built on the (71) algorithm．Routing protocols in internet works differ slightly from the idealized graph model．In an internet work，the goal of the routers to forward (72) to various networks．
Routers running RIP send their advertisement about cost every (73) seconds．A router also sends an update message whenever an update from another router causes it to change its routing table．
Routing protocols use different techniques for assigning (74) to individual networks．Further, each routing protocol forms a metric aggregation in a different way．RIP takes the simplest approach，with all link costs being equal (75) ．Thus it always tries to find the minimum hop route．Valid distances are 1 through 15．This also limits RIP to runing on fairly small networks．

A．1
B．15
C．16
D．length of the link