Mobile homes (移动房屋), pulled by specially designed trucks, have been increasing (增长) in numbers all over the United States. Often, driving along, you can see some mobile homes high on the hill. Some stand under trees along a river or a lake. They’re wonderfully built homes. Sometimes they’re as much as 40 feet long, with two to five rooms, and you can find many things you need in them. When you part your mobile home, water, electricity power and telephones are connected, and you can enjoy yourselves there.

   The fact that these homes can be moved doesn’t mean that they do move all the time. Sometimes their owners stay for years in one place, plant gardens, build walls and so on. These homes are quite expensive. Some even cost $20,000.

Why does a family choose to live in such a home? Well, it’s comfortable, easy to keep clean, easy to keep warm, no need to paint. What’s more, the fast increase of mobile homes in numbers has something to do with the job uncertainty. Nobody knows what will happen tomorrow. If a factory closes down, you may be trapped with the house you can’t sell. However, if you have a mobile home, you can move easily.

The greatest selling attraction (吸引) of these mobile homes is that they can be improved every year. If you are doing well, you may change a new model just as you do with a car. There is a ready market for used ones, so the price of the mobile homes is higher than that of cars.

When it comes to the greatest inventions of the world, China’s name is sure to be mentioned several times. There are hundreds of things which were invented by the Chinese.

Alcohol（酒）

When we talk about alcohol, we think of the US or the UK. But it is also very popular in China. Alcohol, in China, was made by two great persons named Yi Di and Du Kang who belonged to the Xia Dynasty（朝代）. This period was about 2000 BC—1600 BC.

Tea

China is the proud inventor of tea which was first drunk by Shen Nong, a Chinese emperor around 2737 BC. Tea production was greatly developed, making tea a popular drink during the Tang and Song Dynasties.

The Mechanical Clock（机械表）

Have you ever wondered what on earth we would be doing without any idea of time? A clock really is an important invention. Without it, we can’t find a right time to finish things. The first mechanical clock was made in ancient China. It was invented by Yi Xing in the Tang Dynasty. This was during 618 AD and 907 AD.

Silk Fabric（织物）

Silk, the favorite fabric of many girls, is also a Chinese invention. Although we all know that silk is made by silkworms（蛋）, it was Chinese people who first invented a way to produce the silk and then used it to make clothes. The oldest silk which has been found so far is in Henan Province and dates back to 3630 BC.

People celebrate World Health Day on April 7 each year. The day is used to stress the importance of personal health. In fact, there are many new inventions that can make our lives healthier and safer. Let’s take a look at some of them.

We usually brush our teeth without thinking too much about what we’re actually doing. To make sure your focus is back to the task at hand, dentist Craig Kohler from the US created the world’s first toothbrush with a built-in HD camera. It lets you closely monitor the inside of your mouth when you brush your teeth to get them cleaner than ever. The toothbrush can connect to smartphones and tablets with Wi-Fi and Bluetooth. You can even zoom in and out (放大或缩小) of certain areas of the mouth.

Can you use your smartphone to “wash” your hands? You read that correctly. A South Korean company has created a digital sanitizer (电子洗手液) called UVLEN. Attach it to your phone’s torch and it can clean your hands with a high-tech ultraviolet light (紫外线光). It claims to kill germs and viruses, including the coronavirus, in 10 seconds. It is said to kill germs without harming your skin.

An invention that combines a broom and vacuum (真空吸尘器) has been created. It looks like an ordinary broom, but its designers say the VaBroom will clean up common household dirt and debris (垃圾碎片) -all without a dustpan (簸箕)! The vacuum is really easy to use. Just tilt (倾斜) the broom — you don’t even need to bend over — and press the vacuum part to the floor. It is powerful enough to deal with most debris, including glass and candy.