The pronunciation of key is [ yào shi ].

Keys are a common lock-opening tool in people's lives, and the materials used to make keys are mainly copper, zinc, aluminum, iron and other metals. The invention of the key is later than the lock, 4,000 years ago has appeared in ancient Egypt. There are many types of keys, including ordinary keys, smart keys, remote control keys, electronic keys and so on.

Key classification:

1, finger-ring key: the ancient Romans were wearing robes, and robes according to the customs of the time is not allowed to do the pocket. In order to prevent going out when the key is lost, so the production of finger-ring key, go out and put the key like a ring on the finger, both safe and beautiful.

2, honeymoon key: more than 100 years ago, many hotels in the United States are equipped with a special kind of key, called the "honeymoon key", refers to the honeymoon of the newlyweds specifically for the preparation of the couple must be at the same time to insert their respective keys into the lock hole, the door can be opened.

3, power-saving key: Singapore's tourism industry is very developed, the hotel power consumption is also amazing. Experts have invented a power-saving key to connect and cut off the power supply in the guest room and link the use of customer keys. When the guest leaves the room, locks the door and pulls out the key, the power-saving device begins to work, greatly reducing the power consumption of the hotel industry.

4, "lock cold window" key: China's earliest surviving key is the Tang Dynasty (731 AD) cast bronze key. Its shape resembles the window panes of the ancient Chinese incense pavilion, known to collectors as the "lock cold window".

5, the golden key: in a small museum on the island of Elba, there is a world's most valuable key. It is Napoleon gave his wife Josephine a small gold key, someone wants to buy it for 20,000 U.S. dollars, but was rejected.

6, the city's "golden key": if a visitor to a city's golden key, is a very high courtesy, symbolizing friendship and trust.

Baidu Encyclopedia - Key