问题 选择题

海带中含有碘离子,某化学兴趣小组设计如下的步骤从海带中提取单质碘: ①通足量氯气 ②将海带烧成灰,向灰中加水搅拌 ③加CCl4振荡 ④过滤  ⑤用分液漏斗分液。合理的操作顺序为[ ]

A.①→③→⑤→②→④   

B.②→①→③→④→⑤

C.②→④→①→③→⑤     

D.③→①→②→⑤→④

答案

答案:C

单项选择题
阅读理解

阅读理解

     The practice of magic includes special words, actions, and objects. Most magic involves a person

called a magician, who claims to have supernatural powers.  

     Magic words. To work most magic, the magician sings or speaks special words in a certain order.  

These words are called incantations or spells. Some spells form prayers to demons(魔鬼), spirits, or

other supernatural forces. Many societies believe the magic will not work unless the magician recites the

spells perfectly. Other magic words have no meaning, though they supposedly possess power when

spoken by a magician.

     Magic actions accompany the words spoken in performing much magic. Many of these movements

act out the desired effect of the magic. For example, a magician trying to make rain fall may sprinkle

(洒) water on the ground. The magician's combined words and actions form a ceremony.

     Magic objects include certain plants, stones, and other things with supposed supernatural powers. 

Any such object may be called a fetish(物神). But this term often refers to an object-for example, a

carving or a dried snake-honored by a tribe for its magic powers. Many tribes believe fetishes have

magic power because spirits live in these objects.

     Many people carry magic objects called amulets(护身符)to protect themselves from harm. Many

amulets are stones or rings engraved(雕刻) with magic symbols.

     The magician.  In some societies, nearly everyone knows how to work some magic. In other

societies, only experts practice magic. Magicians may be called medicine men, medicine women,

shamans, sorcerers, or witch doctors. In many societies, magicians must inherit their powers. In others,

any person may become a magician by studying the magical arts.

     Many societies believe magicians must observe certain rules and taboos (forbidden actions) for their

spells to work. For example, they may be required not to eat various foods or to avoid sexual activity

for a certain period before the ceremony.

1. What do magic words mean to people in some society?

A. They have the power to kill devils.

B. They have power if magician recites the right spells.

C. They have no effect at all.  

D. They can be used whenever they want.  

2. People believe magic actions will have an effect if they are accompanied by________.

A. the spells

B. magic objects

C. stones or rings engraved with magic symbols

D. medicine 

3. Why do many people believe in a fetish? 

A. Because it is often a ring which is worth a lot of money.  

B. Because it is carved with magic symbols.  

C. Because people think spirits live in it.  

D. Because it can help them with many things.

4. What's the best title of the passage?

A. How Magic Works

B. The Power of Magic

C. How to Practice Magic

D. The Choice of Magicians