(E)
Messages can be sent across the land by means of the electric telegraph; but you cannot put up a line of telegraph posts across the sea. Messages can be sent across the
ocean by radio or by cable(电缆). The cable lies on the sea bottom and it has to have very good insulation. If any part of it is weak, the water will get through and stop all signals .
The first cable under the sea was between England and France. It was laid（放置） in 1851. In 1851 engineers tried to lay a cable across the Atlantic Ocean, but they met a
lot of difficulties. Halfway across the Atlantic the cable broke, and the ship that was laying it had to return.
Kelvin advised that another cable ought to be laid. It was made ready, and put on board a big ship. Kelvin and his friends traveled with it and after many days of hard work, they reached America without breaking the cable. Kelvin himself sent the first
message by cable from America to Britain. Unfortunately only 732 messages were sent through this cable before it broke.
The next cable was laid in 1866, and this time there were no problems. The ship
that laid it was the Great Eastern, one of the strongest ships that have ever been built.
It was driven by powerful engines and also by sails .
1. The undersea cable must be made strong enough to prevent _____.
A.. fishes from eating it B. enemy stealing it
C.water getting through it D. others cutting it
2. The first cable across the Atlantic _______.
A. was the first undersea cable
B. was only laid half- way
C. broke after only 732 messages were sent
D. never broke
3. The undersea cable Kelvin and his Mends laid was between_____.
A. England and France B. America and England
C. American and France D. England and Britain
4. The cable that Kelvin and his friends laid went through __
A. the Pacific Ocean B. the Indian Ocean
C. the Atlantic Ocean D. the Arctic Ocean
5. This passage mainly tells us _______.
A. how Kelvin laid the cable
B. how the scientists discovered the cable
C. the history of the cable in the world
D. how to lay the cable in the sea
