The sheepskin raft (羊皮筏), the oldest means of transportation along the Yellow River, has a history of nearly 2,000 years. The airbag of the raft is made of     1     whole sheepskin and goes through many processes including heating to remove hair, soaking in salty oil, sewing, drying     2     blowing. Then the airbags     3     (fasten) to a wooden stand, enabling its use for transporting people and goods across the water.

It is said that the largest sheepskin raft in old times     4     (consist) of more than 600 sheepskin airbags, with an impressive length of 22 meters and a     5     (wide) of 7 meters. It was capable of carrying around 30 tons of goods and drifting over 200 kilometers in one day.

In the early 20th century, before the 1950s,     6     railways were not yet in operation and road traffic was     7    (convenient), the sheepskin raft served as the most important means of transportation for residents     8     (live) along the Yellow River.

However, with the rapid development of society, the sheepskin raft has largely played its historical role     9     transporting people and goods. Nowadays, it can only be found along the banks of the Yellow River in some cities in Gansu province. It has become a tool for people     10     (do) some sightseeing on the Yellow River.

People need transportation to move from one place to another. As time went by, transportation methods improved. Especially after the invention of airplanes, they made travel more convenient and     1     （easy）.

The airplane     2     （invent）by Orville and Wilbur Wright in 1903.     3     first airplane, Wright Flyer I, flew 36.5 meters in 12 seconds. After that, the two brothers kept     4     （improve）their airplanes. They     5     （fly）in public in France in 1908, and started taking passengers with them. Ever since, many other people made great efforts to improve and develop airplanes. Thanks to their efforts, airplane technology developed     6     （extreme）fast.

Today, airplanes have many different     7     （apply）. People can use airplanes to travel to other countries, send urgent mails and help people     8     danger. They use airplanes to send water, food, medicine, etc. to cities that need help. However, airplanes are not only used in positive ways,       9     they are also used to fight wars.

Many things     10     （change）since the invention of the airplane. Airplanes have made travel or transport faster. Airplanes have really changed our lives.