Mrs. Mueller, our next-door neighbor, had lost her husband and she didn’t have children. She was _______ to us. My sister Laurel and I considered her our special friend.

Early in December, Mrs. Mueller went into the _______ . We considered what present to give her after her being well again. We knew she would be home a few days before Christmas to a（an） _______ house with no holiday decorations（装饰）. We lit upon the idea of decorating a small tree with lights and cheer to greet her. We _______ how to carry out our plan when the answer appeared.

I was in Miss O’Keefe’s class. We had decorated a small beautiful _______ in art class. Best of all, it had to be taken away from the classroom _______ Christmas vacation.

Miss O’Keefe said there’d be a drawing（抽签）for the tree. We’d each write our name on a paper and put it in the shoebox. The last day before the _______ , she’d draw a name from the box, and that student could take the tree home.

As I put my folded _______ into the box, I whispered（低语）to Miss O’Keefe that I really hoped I’d win the tree because my sister and I wanted to give it to our _______ . I was certain to get it for our good reason: We wanted to make Mrs. Mueller ________ .

The day came. Miss O’Keefe announced it was time for the ________ . I held my breath as she took the lid off the shoebox, closed her eyes, turned her hand around in the box, and drew ________ out. She opened her eyes, unfolded the paper, looked at it, and announced, “Holly Wheeler has ________ the tree.”

The next day, when Mrs. Mueller’s car came, we hurried over to welcome her back. We ________ as she slowly walked into the house and turned on the lights. Then she saw the tree. First, there was a look of surprise. Then, a sweet ________ appeared, tears filled her eyes. She softly said, “Thank you.”

New York City in the United States has an unusual way of cleaning up its polluted Hudson River: oysters（牡蛎）. It is part of a plan to create a healthier ecosystem in the river by increasing the oyster population. Oysters may help to restore the waters and bring back more sea life. How do oysters do it?

Oysters act as natural “water purifiers”. They are filter feeders（滤食动物）. That means they take in water through their gills and filter out the food in it, such as algae（藻类）, which they then eat. A single adult oyster can filter up to 189 litres of water in a day. As they feed, oysters also filter other harmful things out of the water.

One of these is nitrogen, a chemical found in septic tanks（化粪池）. Sometimes nitrogen gets washed into rivers and oceans when it rains. Too much nitrogen in the water causes much algae to grow. The algae uses up the oxygen in the water, which can harm other sea life. Oysters filter nitrogen out of the water and use it to grow their shells.

Oysters also build reefs（珊瑚礁）, which are important to the whole ecosystem. Oysters attach（依附）themselves to hard surfaces underwater like rocks. Then more oysters attach themselves on top of those. As the oysters grow, their shells mix together to form a reef. When the new oysters are placed in the Hudson River, they are attached to metal cages in the water. These become the foundations for new reefs, which will get larger as more oysters build on top of them.

Oyster reefs provide homes for plants and animals. Reefs also help to protect the shoreline. Large reefs reduce the effect of waves coming in from the ocean, and help to reduce flooding and protect the coast.

Over the years, the New Yorkers have done a lot for the river, but it will still take tens of years before the new reefs being created in the Hudson River grow as the reefs that were destroyed long ago, but there are already signs that the ecosystem is healthier.

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Alvin, 66, was deep in the woods in Grand Cane, Louisiana, last December when a broken balloon like litter caught his eye. Attached was a piece of paper decorated with sparkly star stickers. It was a child’s New Year wish list. He picked it up. He was going to make the child’s wish come true.

On January 2, 2021, Alvin posted a photo of the balloon and the New Year list on his Facebook, looking for the sender. Soon he saw the number of people sharing his post creep into the hundreds, Alvin knew his hope grew into expectations and they were going to find the child named Luna.

It had been a hard year for Flores and her girls. As COVID-19 spread, the family felt lonely and scared.

On a particularly tough day in December 2020, Flores thought of having the girls send letters about wishes by balloon. The twins were excited. Flores helped them compose their letters, including all the things they wanted, and put the notes into red balloons. They sailed them above the trees into the sky, releasing their wishes to the universe.

One day in early January 2021, Flores received a call from her friend, “Someone found Luna's balloon.”

“My jaw dropped,” Flores says. She logged on to Facebook and saw Alvin’s post. People from all over were asking if they, too, could be part of satisfying the wish list.

_________But she hesitated (犹豫) before reaching out to Alvin. She hadn’t really expected anyone would find the balloons, let alone offer to buy gifts for her daughters. She gave him a call.

Back in Louisiana, Alvin got busy collecting toys from his newfound Facebook community, sending them off with a note signed “Alvin the Elf”. Then he found a perfect puppy.

One morning, just as chilly and windy as the day the twins waved goodbye to their balloons, in April 2021, Alvin and his wife drove to Oklahoma City. He let the puppy run to the twins, who shouted with joy when they learned it was theirs.

Later, both families sat down together to share homemade tacos. They all agreed—it felt as if they had known each other forever. They kept in touch almost daily.

Now, after having received so much generosity, Flores and her girls intend to pay it forward.

After all, Alvin went more than the extra mile. “He could have just thrown that balloon in the trash, but he wanted to find Luna,” Flores says.