Ғ. Н.Қисметова Ағылшын тілі грамматикасы

or water transport. Another drawback of air transport is that whereas a 
ship, truck or train whose engines break down can stop until they are 
mended, an aircraft with the same trouble must land. This means that an 
aircraft must have several engines and this increases its cost. Safety 
precautions for air transport also tend to make it expensive. It cannot be 
relied upon for regular services in places or seasons with low clouds and 
mist. The great advantages of air transport being its high speed, all 
civilized countries try to develop it. If you want to save time, you will 
naturally fly by air.
2. Balloons. The earliest form of air transport was balloons, which 
are sometimes called "free balloons" because having no engines they are 
forced to drift by the wind flow. This fact alone makes balloons no! 
reliable enough for carrying people. If they were safer, they would be used 
more for transportation, but at .present the scientists use balloons mostly 
for obtaining information about the upper atmosphere, its density, and 
other scientific subjects. Weather balloons are particularly used by 
meteorologists. They carry instruments whose readings are automatically 
sent back to the ground by the radio, the position of the balloon being 
obtained by radar. Small balloons released from air-fields are 
observed 
to 
obtain the direction and strength of the wind.
3. Aeroplanes. The heavier-than-air machines called aeroplanes were 
rather slow in being adopted for transport. The first aeroplane flight was 
made in 1884.
World War 1 quickened the development of aerqplanes
enormously. By 1918 they were no longer unreliablelfthings
capable of only short1 flights, but powerful machines able to

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