【推荐2】Sulfur dioxide(二氧化硫)is an important compound in its own right。It is used in the manufacture of paper。When made from wood pulp or from other materials，paper is usually pale yellow in colour。 Sulfur dioxide is used to bleach(漂白)it to the white colour which is needed。Sulfur dioxide is used in preference to chlorine as it is less harmful to the environment。Sulfur dioxide is also used in the food industry。It is used to kill bacteria in foods to prevent them from ‘going bad’。Examples of foods where it is used include dried apricots(杏脯) and wine。
When concentrated，sulfuric acid(硫酸)is very dangerous。It is a powerful dehydrating agent and oxidizing agent and can cause very severe burns。
The dehydrating properties of the concentrated acid can be demonstrated in the laboratory by its reaction with sugar。Sugar is a carbohydrate-it contains carbon，hydrogen and oxygen。The concentrated acid removes the hydrogen and oxygen as water，leaving carbon behind。The acid will dehydrate other carbohydrate materials，such as paper，clothing and wood，in a similar way。When dilute，sulfuric acid is safer，but it is still a strong acid with normal acid properties。
(1)To bleach paper to the white colour，Sulfur dioxide is a better choice than chlorine because        。

A．it is less harmful to the environment

B．It is cheaper than chlorine

C．It is easier to prepare than chlorine

(2)The following are the properties of concentrated sulfuric acid，except for       。

A．a powerful dehydrating agent	B．a powerful oxidizing agent
C．Food preservatives(防腐剂)used in the food industry

(3)Dehydration is a process of the removal of water，or the elements of water，from a substance。Here，dehydration means       in Chinese。

A．脱氢

B．脱水

C．脱氧