Toothpaste (牙膏) does more than just keep our teeth bright and white. It can be used wisely in many other ways. Here are some helpful tips that can save us time and money.

Traditionally, we take the subway with our subway cards or by scanning QR codes (扫描二维码) on our smartphones. But now, people traveling on the Beijing Daxing Airport Express subway have a new way to take a ride: They can scan their palms (手掌).

To enjoy the service, people need to register (登记) their palm prints on machines in subway stations along the Daxing Airport Express subway line. Then they have to activate (激活) the palm-scanning function (功能) on their smartphones. Once they do this, they can scan their palms at ticket gates to pass through. After they finish the travel, the payment service on their smartphones will pay the money for their ride.

Many people welcome the new technology. They think it helps them to travel faster and more easily. They don’t have to take out their subway cards or smartphones when they want to pass through the ticket gates. And they no longer have to worry when they forget to take their subway cards or when their smartphones run out of battery. What’s more, the palm-scanning technology is very friendly to old people and those who have special needs. Those people may not use smartphones well. This technology makes it possible for them to take the subway without using smartphones.

In addition to Beijing, the palm-scanning technology is also in service in the subway station of Shenzhen. And there are hopes that it can be used in more places like stores and restaurants in the future.

Some say giraffes（长颈鹿） are “living lightning rods” （活体避雷针）. Is this true? On a rainy day in a nature park in South Africa, two giraffes died after lightning（内电）hit them. “Lightning often hits tall things, especially in open places, and the height of the giraffes might make it easier for them to get hit,” said Ciska PJ Scheijen, a South African animal expert.

An adult male giraffe usually stands about 5.5 meters tall, while females are about 4.3 meters tall. There were no trees near the two giraffes. This meant they were more likely to（更有可能地）get hit by lightning. Besides the height, the animals’ body length can also make the problems worse.

It’s something called step potential（跨步电压）. Currents（ 电流）can move between animals’ front feet and back feet through the ground. The larger the space（空间）is, the greater the current is. So bigger animals like giraffes will get hit more easily.

How to, avoid getting hit by lightening?

*Stay away from open places and make as little（少的）contact（接触）with the ground as possible.

*Don’t stand near tall trees or other tall things.

*Stay away from large metal objects（金属物体）such as bikes. Small objects like your phones are usually safe to hold. But you’d better not use your phone.

*Do not take a shower or use the sink（水槽）.

*Unplug（拔掉插头）TVs and washing machines.

*Keep your windows closed. Currents can’t move through glass.