When you watch 3D movies or TV, you have to wear a special pair of glasses. The 3D glasses make the images from the screen look like they are there in the room with you.

    Three-dimensional, or 3D, means having three dimensions（维度）: width, height and depth. 3D technology（技术） is based on the way the human brain（大脑） and eyes work. Because the pupils of a person's eyes are about 6.5era apart（分开）, when we look at something, each eye sees,it from a different angle（角度）. Our eyes send the two images to our brain, and the brain puts them together. The small difference between the image from the right eye and the image from the left eye allows us to see depth.

    When we view pictures and television in two dimensions, each eye gets the same information. That is because the image has no real depth, and there is only one of viewing it. So the goal of 3D technology is to get a different image into each of the viewer. It uses two film projectors. One projects a left eye image and the other projects a right image. The 3D glasses allow us to see a different image in each eye.

    While watching 3D films, we feel that we are in the same environment as the things we're watching. However, it also has its disadvantages. The 3D glasseswork by controlling the amount of light that reaches the eyes. It makes the screen look darker. What's more, people with eye problems may get headaches if they spend too much time watching 3D movies，because their brains need to work harder to "read" the images.

    When was the last time you saw three men running down a forest trail（小径）in the rain wearing flip-flops（拖鞋）？That's what my friend Brandon, Josh and I were doing last autumn. We were looking for a waterfall（瀑布）.We didn't have much time to get to the waterfall and back, so we were running. We were wearing flip-flops to prevent our shoes getting dirty.

    It was raining, but lightly. It kept us cool as we climbed over giant stones and through a shallow（浅的）stream. We followed red arrows（箭头）and crossed that stream several times, walking on toward the promised waterfall. Time was not on our side, however, and we were forced to turn around. As we started back, we looked at the shallow stream we had just crossed. Where did this rushing river come from? That was when we realized a flash flood was around!

    In the few minutes the water rose at a fast speed. Now there were no big stones to be seen-only what looked like lumps（隆起）covered with rushing water. We had no choice but to move our way back carefully in the rushing water -in flip-flops. We had crossed the stream not once or twice, but six times in search of a waterfall that we never even reached!

    With most of the crossings, we needed each other's help if we didn't want to be washed away by water. Wet all over, we felt relaxed after we made the last crossing.

    "My dad always told me to keep off a river when travelling in the rain." Josh said as we hurried back down the path.

    "Why didn't you tell us that earlier?" I laughed.

    "Would it have made a difference?" came the reply.

    He had a point.

    Devon Gallagher, a college graduate from Philadelphia, wants the world to know exactly where she's been during her worldwide vacation in a special way.

    The traveler, who was born with a congenital bone disease (先天性骨病),lost her right leg at the age of four. Although she had a hard time at first, she now thinks that nothing can stop her living her best life.

    To spread that message, Gallagher shares photos of her travels around the world online, and writes her location across her artificial leg (假肢)before taking a picture. Now she has been taking pictures across Europe, all with the well—known locations written on her artificial leg.

    "I get a new leg every two years and I can choose the design (设计)on it. One day I had a sudden idea to get a chalkboard," Gallagher said, "My mum and grandmother didn't like the idea, but my friends liked it and told me to go for it, so I did."

    Gallagher said people often stared when she was writing on her leg, but once she shared the photos, she received only positive feedback (正面的反馈). "My leg hasn't stopped me doing anything I've wanted to do, and I've been able to keep up with my peers (同龄人)and lead a pretty great life."

    Gallagher shows us that you should never let anything stand in the way of your dreams. And if you run into difficulties, get creative with it because if life gives you an artificial leg, make art.

Hello, everybody. My name is Jimmy Green. I am thirty years old. I am from New York. I work at a lost and found office in New York. At the lost and found office, there are some different things. Let's have a look.

Look! There are five wallets on the table. When you open the wallets, you can find some money in two of them. There is a shelf behind the table. There are some mobile phones and cameras on the shelf. Maybe we have about one hundred cameras. Are these your cameras? Come here and have a look. You miss your camera. Maybe your camera misses you, too. After finding it, you can take it home.

We are open from 9:00 a.m. to 5:00 p.m. from Monday to Friday. We don't close at noon. Welcome here! Maybe you can find what you have lost.

A relaxing walk along the Beijing Central Axis （中轴线），from the Drum Tower to the Palace Museum ﹣this was Zhao Xianghan's first citywalk in 2022. Since then，Zhao has been crazy about the citywalk and believes it is the best way to lear about a city. 

"I visited Beijing before the start of my college life here，but I went there with a guide group. Taking photos of places of interest was a big thing. The crowded places made me think that Beijing was noisy，" said Zhao. "Yet now a citywalk allows me to see a whole different side of Beijing，"Zhao added. 

Zhao travelled in Wuhan and Hangzhou last month through citywalk tours. "Citywalk is all about doing whatever you want in your own traveling. And I enjoyed it so much，" said Zhao. 

People like Zhao also share their citywalk experience on the Internet. On the video﹣sharing app Douyin，a video about citywalk route （路线） by Chen Dong in Guangzhou got more than 171

Zhang Xinyu，a 19﹣year﹣old girl from Beijing University，shared a citywalk route from Wukang Road to Fuxing Park in Shanghni. "I like the route because I can know more about the culture and beauty of Shanghai