文档介绍：Step 1
Presentation
What are they doing?
1
2
3
Introduction
Step 2
4
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Early Telephones
Alexander Graham Bell's Telephone
Alexander Gram Bell speaks into his telephone
Step 3. Reading
Read the passage then find the answers
to these questions
How was one telephone connected with
another in the past?
is one telephone connected with
another today?
By thick heavy wires.
By satellite.(by very thin glass pipes)
Listen to the text and Answer the following questions:
does a telephone work?
voice(sound wave)→ electrical signals —a pair of lines— electrical signals→sound wave
Speaker phone
Step 4
listening
the receiving
Early
telephone
about the wires?
to make a call with a handle telephone?
not popular (took a long time ) ─ buy,hire ─hear
handle telephone →wind (electricity)→ operator→ connect,note
the earliest telephones popular?
was the first telephone directory printed?
how many telephones in 1877 and in 1990?
.telephone ┌①USA 1878
directory ├②1877 ,2600
└③1990 , 300 million
Step 5. Retelling the passage
?
Speaker phone
the receiving phone
voice(sound wave)
electrical signals
a pair of lines
electrical signals
sound wave