The Grand Canal of China was first dug in 486 BC, and well developed through the late 6th to early 10th century. From the late 13th until 19th century, with the highest section built and the overall length     1    (shorten), the Canal was turned into a main passage between northern     2     southern China as well as the economic lifeline of the country. Consisting of the Sui and Tang Grand Canal, the Jing-Hang Grand Canal and the Zhedong Canal, the Canal     3    (stretch) over 2, 700 kilometers, crossing eight provincial-level administrative regions and     4    (link) five major water systems. The Grand Canal also connects with the Eurasian Silk Road to the west and extends the water trade route to the east.

The Grand Canal was     5     notable achievement of the ancient Chinese people. Its connection of the political and economic centers played a     6    (centre) role in the political unity, economic     7    (grow) and cultural prosperity of China, and contributed to the livelihood, exchanges and integration of the population along its route.

The Grand Canal     8    (announce) by the State Council as one of the seventh batch of Major Historical and Cultural Sites Protected at the National Level in March, 2013 and registered     9     the UNSECO World Heritage List in June, 2014. This large-scale, living cultural heritage spreads like a huge dragon across the vast territory of China,     10    (it) ripples shining golden scales (鳞片) in the new age.

3 . Try to picture the world before refrigerators. That may be difficult!     1     They may also help store leftovers there after dinner. Yes, life today would be quite different without refrigerators. How did people keep their food fresh before these machines were around?

    2     In cold areas, ancient people could freeze their food. They could then store it in ice and snow. Warmer places allowed for drying food in sunlight. Experts say these early practices gave people the option to settle and form communities.

One advanced method of food storage arose in Persia around 400 BC. People there stored food in structures called Yakhchal, which were buildings made from mud brick to keep ice frozen during even the warmest summer months. During the Middle Ages, people stored meat by salting or smoking it.     3     These foods could then be stored in cool places, like caves, allowing people to save food for difficult times.

Later, buildings called ice houses or ice pits were built upon the idea of the Yakhchal. Such ice houses were very common by the 1800s. At the end of the 19th century, many people kept their food fresh in iceboxes made of wood.     4     Ice delivery businesses grew with more homes requiring ice to store food.

By the 1930s, many people were using electric refrigerators to keep food fresh.     5     Many refrigerators today come with built-in ice makers. Some people even choose smart refrigerators that can help them with meal plans and grocery shopping.