Unit 6
[Listen and Write]
In 1876, Alexander Graham Bell invented the telephone. He was a teacher who taught deaf people how to speak. He also learnt how people make sounds and how we hear them.

In those days, people used to send messages one at a time by telegraph. Bell’s first invention allowed many messages to be sent down one wire at the same time.

Later, he made a microphone that could send sounds down a wire. Then, he made a receiver that could collect sounds from a wire. These became the two main parts of a telephone.

[Memorized Dictation]