53.
What is the passage mainly about?
A. Ocean exploration.
B. A scientific plan.
C. A scientific discovery.
D. An interesting experiment

D
Runners
in a relay(接力)race pass a stick in one direction. However, merchants
passed silk, gold, fruit, and glass along the Silk Road
in more than one direction. They earned their living by traveling the famous Silk Road.
The
Silk Road was not a simple trading network. It
passed through thousands of citied and towns. It started from eastern China, across Central Asia and the Middle East,
and ended in the Mediterranean Sea. It was
used from about 200 B, C, to about A, D, 1300, when sea travel offered new
routes(路线), It was sometimes called the world’s longest highway. However,
the Silk Road was made up of many routes, not
one smooth path. They passed through what are now 18 countries. The routes
crossed mountains and deserts and had many dangers of hot sun, deep snow and
even battles. Only experienced traders could return safe.
The
Silk Road got its name from its most prized
product. Silk could be used like money to pay taxes or buy goods. But the
traders carried more than just silk. Gold, silver, and glass from Europe were
much found in the Middle East and Asia. Horses
traded from other areas changed farming practices in China. Indian merchants traded salt
and other valuable goods. Chinese merchants traded paper, which produced an
immediate effect on the West. Apples traveled from central Asia to Rome. The Chinese had
learned to graft(嫁接)different trees together to make new kinds of fruit. They
passed this science on to others, including the Romans. The Romans used
grafting to grow the apple. Trading along the Silk Road
led to world-wide business 2,000 years before the World Wide Web.
The
people along the Silk Road did not share just
goods. They also shared their beliefs. The Silk Road provided pathways for
learning, diplomacy(外交), and religion(宗教)