2 . Sometimes friends hurt other friends’ feelings without meaning to. If you are being joked on and feeling upset, just say something. And if you are among the ones doing the joking, make sure you pay attention to how your friend feels.

—A lesson from my experience

One day, Mareya, Ollie, Jasmine and I were kicking a soccer ball in the park, and Jasmine kept singing a song over and over. It sounds very ________, which quickly caught our attention.

“The tune (曲调)is pretty pleasant,” said Mareya happily. “Do you remember the ________?”

“Let me see...”Then Jasmine started singing this song ending with “Mar-eye-aaa, Mar-eye-aaa. They called the ________ Mar-eye-aaa.”

“That’s so great!” said Ollie. “Mareya, how come you never told us you were the wind?”

“Hey, Mar-eye-a!” I ________, “Can you use your power to blow that soccer ball over here to me?”

“No!” said Jasmine. “Please use your strong power to ________ the ball in my direction!”

Then Ollie started singing quite loudly. “Mar-eye-aaa, Mar-eye-aaa. They called the wind Mar-eye-aaa.”

His voice was so ________ that we couldn’t help laughing like crazy. ________, we paid no attention to Mareya.

A couple days later, when Ollie and I went to the park for a ________, Mareya and Jasmine happened to be there, too.

“Hey there, friends!” Jasmine called to ________.

As we skated over to them, Ollie sang, “Mar-eye-aaa, Mar-eye-aaa. They called the wind Mar-eye-aaa!”

Jasmine and I laughed and began to sing along.

Mareya’s smile ________ suddenly. “Can you please just stop?” She cried out angrily.

Surprised, Ollie, Jasmine and I stopped.

“I couldn’t ________ why I felt so angry the other day,” Mareya said. “________ when it happened again just now. I got it. I can’t stand it!”

Only then did we realize that we ________ her without meaning to. “We’re really ________! Could you please forgive （原谅） us? And thanks for telling us your true feelings!”

“It’s OK. But never do it like this anymore?” she said ________.

“We promise!” we all said at once. And this time, all four of us really and truly did laugh together!

Each time I take the underground I find the subway is     1     (fill) with lots of passengers playing smart-phones. They almost won’t even look at the outside world. You may think it is normal     2     (play) smart-phones to kill time. What’s     3     (badly), when I talk with some of my friends, they talk as playing. I really miss the old days when I     4     (chat) with some passengers on the train. Now things are different. Everyone just pay attention to their smart-phones. When     5     (talk) with them, it seems that you influence them. I could not just blame (责备) them for I am moving to be one like them. Once in     6     while, I just feel we leave out our neighbors. Also, I think we just want to keep in touch with     7     (strange) on the Internet. We care about the things far away     8     pay no attention to the needs nearby. In a way we     9     (control) by smart-phones now. Are you experiencing the same situation like me? Do you have any ways     10     avoiding that?

8 . Have you heard of a bike bus? It carries a group of children to school in the same way a school bus does, except everyone is on bikes. The “bus driver”—an adult on a bike—guides a slowly moving group along a route (路线) that has already been chosen. Kids and their parents join the group on their own bikes when the group rides by.

Bike buses are a way for everyone to bike together for fun, convenience and safety. On busy streets, a big group of five to ten kids is much more visible (明显的) than one or two kids biking alone.

Sam Balto is a PE teacher. He leads a bike bus to school. His bus is especially visible because it has hundreds of shouting kids and parents. It stretches out over several blocks (街区). Sam vlogs his bike bus trip. As the parent of two kids, I can’t watch his videos without crying. The bike bus calms my fear that the kids will get hurt on the road. Laughing kids! Outside, in person! Together! So when a friend asked if I would lead a bike bus in our neighborhood, of course I said yes.

Using active transportation to go to work and school—whether that’s a biking bus, or even a walking bus—has many advantages. Yes, people are healthier and happier when they’re more active, but reducing the number of cars around a school can also reduce heavy traffic and air pollution.

I was shocked by what starting or driving a bike bus meant to different people. For Luke Bornheimer, the leader of the San Francisco Bike Bus, it’s amazing to see children take care of themselves. “Kids are really smart and strong.” Bornheimer says. “They get how to ride responsibly (负责任地) and have fun. We’re just giving them that chance.” For me, the bike bus was the start of rejoining my community. My kids love the bike bus, but we parents might love it even more. We talk about everything, from the bike bus to other topics, such as planning neighborhood roller skating meetups and party nights.

I do accept that getting more kids to safely bike and walk in more places will take a lot more work than parents just trying to get their kids to school every day. But our efforts are a start. We live on a planet that has many environmental problems. Maybe the best way to remind ourselves that we and the Earth are worth (值得的) protecting is by moving through it, not in cars, but with fresh air on our faces and the sounds of kids’ laughter echoing in our ears.

9 . Air pollution is one of the world’s invisible killers. It causes seven million deaths a year, making it the largest single environmental health risk. In cities, air pollution is particularly serious. More than 80% of people live in the areas where pollution levels are beyond WHO limits.

One well-established way to reduce air pollution is to plant trees, as their leaves catch and absorb harmful particulates (微粒). But planting new trees is not always a good choice for lack of enough space. That’s why the “City Tree”, a mobile tree which removes pollutants from the air, has been becoming popular in cities around the world, including Oslo, Paris, Brussels and Hong Kong.

Each City Tree is just under 4 meters tall, nearly 3 meters wide and 2.19 meters deep, acting as a chair or a bench. A screen is included for information or advertising. Berlin-based Green City Organization explains that its invention has the environmental benefit of up to 275 actual trees.

But the City Tree isn’t, in fact, a tree at all—it’s a moss culture (青苔培植). “Moss cultures have a much larger leaf surface area than any other plant. That means we can catch more pollutants,” said Zhengliang Wu, co-founder of Green City Organization.

The huge surfaces of moss in each tree can remove dust, NO₂ and O₃ gases from the air. It requires very little care: solar panels provide electricity, while rainwater is collected into a container and then sent into the soil.

To monitor the health of the moss, the City Tree has sensors which measure soil humidity (湿度), temperature and water quality. “We also have pollution sensors inside the trees, which help monitor the local air quality and tell us how efficient the tree is,” Wu said. Its creators say that each City Tree is able to absorb around 250 grams of particulate matter a day and contributes to removing 480 tons of CO₂ a year.