Did you ever wonder how some of your favorite foods, products or toys came about? Believe it or not, they may have been an accident, or a failure of some other intention. Below, we found three mistakes we're thankful for turned out to be what they are.

1. Most historians hold that the Chinese invented fireworks in the 9^th century when they discovered how to make gunpowder. Story has it that a Chinese cook accidentally mixed together what were then considered common kitchen items and noticed they burnt. When put tightly in a bamboo tube and lit, it blew up.

2. In May of 1886, a law led John Pemberton, a pharmacist(药剂师), to rewrite the formula(配方) for "Pemberton's French Wine Coca", his popular headache treatment. Containing sugar instead of wine as a sweetener, the outcome became something for Coke, which was later mixed with carbonated(碳酸) water. His bookkeeper suggested the name Coca-Cola because he thought the two C's would look good together, which is how what we call Coca-Cola, a world-wide drink came into being.

3. During World WarⅡ, scientists at the University of Birmingham invented the magnetron(磁控管)—an important heat-producing part of the microwave oven. While working for Raytheon Corporation after the war, the American engineer Percy Spencer was testing the magnetron when a chocolate bar in his pocket melted. He went on to test other foods including popcorn kernels(仁), and found it to be a much more efficient way to cook. In 1947 Raytheon came out with the first restaurant microwave oven, which was six feet tall and weighed 750 lbs.

    Job interviews can be very different from country. An interviewer's “body language” and questions, and the form of an interview are not the same around the world.

    If you're at a job interview in Japan, don't look directly into the eyes of the interviewer. It is considered impolite. But if you're at an interview in the US, you should make eye contact(交流) with the interviewer. If you don't, the interviewer may think you are not sure about your ability.

    In the US and some other countries, interviewers aren't supposed to ask questions about family and personal information. In most countries, however, personal questions are very common during job interviews.

    In Germany, your interview might begin with a very short conversation followed by a formal(正式的) interview. In Mexico and many other countries, the whole interview might not be formal.

    Different countries have different customs(风俗) in the world. It's very important for us to know about them.

    When you go to the US, someone often says to you "give me five". What should you do? Do not get five dollars from your pocket! It will make others laugh! The person is not asking for your money, but your fingers.

    In the US, "give me five" or "give me the high five" is a popular gesture. You can see it often in films or on TV. It means hitting(敲打) each other's right hands together.

    People do it when they meet for the first time or something happy happens. For example, a student good grades in exams. If a football teams wins a game, the players will give high fives to everyone around to celebrate.

    This gesture may come from the old Roman gesture of raising the right arm for the empor. This showed the person raising his arm did not have a knife in his hand.

    Why not try to give the high five to your friends?

    You have probably heard the popular Australian greeting, "G'day mate!"

    G'day is a short form of "good day". And "mate" is the same as "friend". Some think that "mate" came from the word "shipmate", used by people working on ships.

    But Australian English is much more complex(复杂的) than just saying "G'day mate!". There are many special words and expressions in Australian English when you see someone you know. For example, if you're being lazy you're a "bludger". If you crash your car you've just had a "pulling a sickie".

    Australian English is a funny mixture(混合体), because English and Irish(爱尔兰的) criminals(罪犯) were sent by the British to Australia. They brought their slang(俚语) with them.

    Also, it's because there are so many special plants and animals in Australia. Many of their names come from Aboriginal(土著的) English, like "Kangaroo" and "Dingo".

    Nowadays, Australians watch a lot of American television and listen to American music. That has a large effect(影响) on the way they speak.

    There are actually three types of Australian accent(口音), but the most well-known is Broad Australian English. It is common in country areas. It's the most difficult to understand.

    So next time you meet an Australian, remember that there's a reason they sound so special!

    A city without cars would be very strange, right? But Venice is such a city.

    Venice is in the north-east of Italy. It wasn't built on land, like Beijing or Shanghai, but on more than 110 islands. Seawater is everywhere around the city.

    Even so, travel isn't difficult. The waterways have always been the best way to get around. There are 177 waterways and more than 400 bridges that can guide you where you want to go. People in Venice move from place to place by boat. They like to enjoy the scenery and the cool summer night while taking boat trips. They can talk to other people as they go along.

    Venice grew out of small islands in saltwater lakes when some Italians escaped from a war over 1, 500 years ago, and built homes there.

    Water makes the city special, but it is also a big problem. Sometimes tourists will have such strange experiences. One moment they walk across the Rialto Bridge, and there's nothing special but when they come back to the bridge an hour later, it's underwater and everyone is wearing rain shoes.

    Once, people used too much underground water. This made the city get lower little by little. Now the city has gone down by 23 centimetres. Another problem is the rising seawater. The temperature has risen over the years. This has made the ice of the Arctic Ocean (北冰洋) melt (融化).

    Every year, high waters hit the city in autumn and winter. When a lot of water comes, more than half of the city is underwater.

    Scientists are trying different ways to stop the city from getting even lower. The Italian government has asked some of Italy's biggest companies to build the MOST project, which was planned to be built under the seawater to stop the rising water. Anyway, this project is helping solve the problem.