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Unit 4 Inventions and Inventors
Expansion 4
Exercise 1
Have you ever asked yourself
why the letters on your computer keyboard
are placed in this strange way?
Why are the keys not ordered
according to the order of letters?
To explain this ,
we have to go back to the invention
of the typewriter,
Keyboards on the earliest typewriters were
made with the keys in the order of leters ,
It was easy to find the letters,
but this system had a big disadvantage.
When a persom typed letters that
are often found together in English words ,
the keys often got stuck because these letters
were so close to each other.
Christopher Latham Sholes,
one of the inventors of the typewriter,
invented a new keyboard system
to solve this problem.
The first six leters on this new keyboard were
Q,W,E,R,T.and Y.
So the system is called the QWERTY system.
Letters that often appear together
in English words are placed far apart
on the QWERTY Keyboard.
Nearly all keyboards today use this system.
Even though someone could invent a new ststem.
everyone is so familiar with the QWERTY system
now that it will probably never be changed.
Exercise 2
The Morse Code is a simple communication system.
In this system.
Short dots(•) and longer dashes(-)are used to
represent the letters.
If you listen to the Morse Code,
a dash is three times as long as a dot.
The Morse Code was developed in the 1830s
by the American inventor,Samuel F.b. Morse.
with help from other scientists.
The Morse Code is rarely used today
because modern communication methods
are easier and faster.
However,it is sometimes used in emergencies.
For examle,
a person who is covered under a building
after an earthquake can call for help
using the Morse Code.
The well-known message SOS can be easily
remembered:dot-dot-dot,dash-dash-dash,
dot-dot-dot.
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