简述网络安全的五要素。
题型：问答题 简答题
问题：
简述网络安全的五要素。
题型：问答题 简答题
Is it a tree? Is it a bear? If you’re looking at a tree in the shape of a bear, it’s a topiary(林木雕塑). A topiary is a tree or a bush(灌木) that is trained into a shape. Growing a topiary garden takes both time and skills. 
A topiary gardener should make a drawing first. The drawing shows the final shape that the gardener likes. The gardener then chooses a bush for the topiary. It may be one that just planted or one that is already in place.
In June of the plant’s first year, the gardener looks for new leaves. When the leaves grow, it’s time to shape(给……造型) the bottom of the bush. It needs about five years. The top is not trimmed during this time. In the fifth year, the bush grows tall enough for shaping. Then the gardener begins to shape the whole bush.
Once a topiary has been starte
d, it needs care all year. In the summer it must be cut many times to keep its shape. This cutting also helps the bush grow. In the winter the bushes don’t grow. The gardeners have to brush snow of the plants, or snow may hurt some parts of them.
Topiary gardening is very old art. The Romans did it in the first Century. In the sixteenth century, people in Europe like topiaries too. By the late 1600s, topiaries were also grown in America. Today it’s popular in many parts of the world.
小题1: Put the following in the right order according to the passage.
a. The gardener chooses a bush for the topiary.
b. The whole bush grows tall enough for shaping.
c. The gardener begins to shape the bottom of the bush.
d. The gardener draws the shape of a topiary.
A．d→a→b→c
B．b→c→a→d
C．a→d→c→b
D．d→a→c→b小题2:In which part of the world did the topiary gardening begin first?
A．In Rome.
B．In Europe.
C．In America.
D．In Africa.