Прочитайте текст и заполните пропуски 1-6 частями A-G (вставив буквы A-H). Одна из частей в списке A-G - лишняя.

Before the invention of the internal combustion engine, the only successful human flights were in balloons filled with hot air or a gas like hydrogen which is "lighter than air". But balloons cannot be properly controlled in flight 1 . Not until man had invented a powered, "heavier than air" machine could he claim to have conquered the skies. Steam-engines were often tried in the nineteenth century, but they were much too heavy in relation to the power they produced. It was the lighter, more compact petrol engine 2 .
Wilbur and Orville Wright were bicycle-makers from Dayton in the USA. In 1903, after carefully studying the problems of flight, they fitted a wooden glider with a twelve horse-power petrol engine and two propellers driven by bicycle chains. On a cold morning in December at Kitty Hawk, North Carolina, they became the first men to fly a "heavier than air" machine.
The British were slow to respond to the new invention. Five years went by 3 . In 1909, when the "Daily Mail" offered £1000 for the first man to fly the Channel, it was won by a Frenchman, Louis, Bleroits. However, when the First World War broke out, five years later, the vast majority of the population had not yet seen an aeroplane. The military possibilities of aircraft were quickly realized, 4 .
For the first time planes were mass produced from standard parts.
The extent of the progress made during the war was shown in 1919, when two Royal Air Force officers, John Alcock and Arthur Whitten-Brown, made the first flight across the Atlantic. They covered the 1890 miles from Newfoundland to Ireland at an average speed of 118 m.p.h., battling all the way against fog, ice and storms. At one point, Brown had to climb on the wings to hack away ice with a knife. In August of the same year, the world’s first daily air service began, 5 . By 1923 Croydon Airport, in Surrey, was handling up to thirty cross-channel flights a day. A high standard of safety and reliability was achieved, 6 .

A. carrying goods and passengers between London and Paris.
B. so the war led to a rapid development of aviation.
C. that lasted only fifty-nine seconds.
D. that held the key to success.
E. although the journey was slow and bumpy.
F. before the first powered flight was made in England.
G. because they are at the mercy of the wind and air-currents.