下列实体的联系中,属于多对多联系的是【 】。A．学生与课程 B．学校与校长 C．

若规定收入为“+”，那么-50元表示（　　）

A．收入了50元

B．支出了50元

C．没有收入也没有支出

D．收入了100元

具有肝药酶诱导作用的药物是（）

A.异烟肼

B.链霉素

C.吡嗪酰胺

D.利福平

E.乙胺丁醇

乾坤一气膏功效与作用

For many years, no one could communicate with people who had been born without hearing. These deaf people were not able to use a spoken language.

But, beginning in the 1700s, the deaf were taught a special language. Using this language, they could share thoughts and ideas with others. The language they used was a language without sound. It was a sign language.

How did this sign language work? The deaf were taught to make certain movements using their hands, faces, and bodies. These movements stood for things and ideas. People might move their forefingers across their lips. This meant, “You are not telling the truth.” They might tap their chins with three fingers. This meant “my uncle.”

The deaf were also taught to use a finger alphabet (字母). They used their fingers to make the letters of the alphabet. In this way, they spelled out words. Some deaf people could spell out words at a speed of 130 words per minute.

Sign language and finger spelling are not used as much as they once were. Today, the deaf are taught to understand others by watching their lips. They are also taught how to speak.

1. The deaf “talked” to other people __________.

A. by moving their hands, faces and bodies

B. by shouting and singing

C. without using any letters         

D. without using any language

2. The deaf could spell out words __________.

A. by reading them aloud

B. by going here and there

C. by expressing the letters with their fingers

D. by watching others

3. Now, the deaf are trained to __________.

A. write sentences quickly

B. understand others by lip-reading

C. be good at mind-reading

D. keep alone happily

4. The story as a whole is about __________.

A. learning to spell                      B. teaching the deaf to speak   

C. how the deaf communicate             D. understanding Indian sign language

简析战国时期变法运动的意义。