Many people catch a cold in spring or autumn. It makes us wonder-if scientists can send a man to the moon, why can’t they find a cure (疗法) for the common cold? The answer is easy. There are hundreds of kinds of coldviruses (病毒) out there. You never know which one you will get, so there isn’t a cure for each one.

When a virus attacks (攻击) your body, your body works hard to get rid of it. Blood rushes to your nose and brings congestion (充血) with it. You feel terrible because you can’t breathe well, but your body is actually “eating” the virus. Your temperature rises, and you get a fever, but the heat of your body is killing the virus. You may feel awful, but your body is doing everything it can to get over the cold.

Different people have different ways of dealing with colds. In the United States and some other countries, people might have chicken soup to feel better. Some people take hot baths and drink warm water. Other people take medicine to stop the fever, congestion, and runny nose (流鼻涕).

There is one interesting thing to note —some scientists say that taking medicine when you have a cold might be bad for you. This is because the virus can then stay in you longer because your body doesn’t have a way to fight it and kill it. Bodies can do an amazing job on their own. There is a joke about taking medicine when you have a cold. It goes like this: It takes about one week to get over a cold if you don’t take medicine, but only seven days to get over a cold if you take medicine.

①Hangzhou, together with five other cities in Zhejiang, hosted the 19th Asian Games from Sept 23 to Oct 8. The 16-day games were very “smart” with the use of many exciting technologies. Let’s have a look!

②The stadium for the tennis finals of the Hangzhou Asian Games is sometimes called the “Small Lotus (莲花)”. On the top of the stadium, there are eight “petals (花瓣)”. Each petal weighs 160 tons. They can open and close freely. It takes 15 minutes for each petal to open and close. It’s built this way for different kinds of weather.

③Every dish at the Asian Games should be safe and healthy to eat. In the kitchen of the athletes’ village in Hangzhou, there is a special system that can tell people’s faces. If a “stranger” goes into the kitchen, an alarm (警报器) will go off to let people know. The managers of the kitchen will also get messages on their phones. There’s also a system to keep an eye on the temperature of the fridges.

④ What if there’s an accident during the game and the athletes need first aid? Drones (无人机) can be used to send things over. They can fly as far as 20 kilometers and travel 16 meters in one second. Using a drone saves about 60 percent of the time, according to the drone maker Antwork. Medicine, blood and other things needed for first aid can be sent to people quickly.

⑤AR is here to help if you can’t find your way. There’s a mini program called the Hangzhou Asian Games AR service. You simply turn on your phone’s camera and it will see where you are and then show you the way. You can also get more information about the stadiums as you walk by.