4 . It was a normal morning in March. Sondra Artis had just _______ the last student on her route.

As heading towards the school, Sondra noticed a burning smell. She _______ the bus window to see if it was fogging up from condensation（凝结）or if it was _______ . When a student asked her what was _______ , she did her best to hide her growing _______ .

Sondra pulled into a parking lot and turned to face the 20 students on _______ . She reminded them of the evacuation（疏散） _______ they once performed and directed them to leave through the doors.

“I told the kids that, ‘You know, we _______ at the beginning of the year, but this is going to be _______ , so I need you to be calm,’” said Sondra.

The students hurried to the ________ as smoke began to fill the bus. They were ________ , but Sondra remained calm. When they were out, she went back onto the bus to make sure everyone left ________ .

Seconds after they all ________ , the bus caught fire. Another bus came to the ________ to take the children away, and Sondra was left ________ that everything worked out okay.

The bus can be ________ , but human life cannot. The parents were incredibly ________ for her grace under fire. She's being considered as a ________ , and many of her students would like to see her ________ for her heroism.

“Sondra is a very good bus driver，”said a student. “She ________ a reward.”

It’s the Saturday, 1:00 am, and Stormy, my dog, and I were going on a pre-dawn bird-watching adventure. The weatherman predicted fog, but as we hit the road, it’s clear. Along our journey, I stopped at a petrol station, ensuring Stormy was safely locked in the truck.

“Stormy, hang tight,” I whispered, stepping out into the night air.

Back on the highway, as we were near the marshlands, a heavy fog began to swallow everything. At a sharp bend, my truck hit soft ground, and I lost control. “Oh, no!” Panic set in as the vehicle slid off the road with a bang, falling down a steep bank and into the water.

In the strange silence that followed, I was floating inside the car, gently carried downstream by the canal. “Come on, door,” I said, switching uselessly at the handle. It won’t move; the electrical system had shorted out due to the water. “I’ve got a glass breaker,” I reminded myself, reaching for the tool in the center part.

With each failed attempt to break the window — the glass bouncing back at me — I felt a growing sense of urgency. Water moved over the floorboards, cooling my feet. “Stormy, stay calm,” I said, lying down to kick at the window with all my strength. But my efforts only met resistance.

As the water level rose threateningly close to the ceiling, fear clawed at my heart. In a last effort, I dived behind the seat for my toolbox. “Got to find something solid.” My hands brushed against the cold metal toolbox, then the fire extinguisher (灭火器). “This might work.”

“Here goes everything,” I thought, holding the extinguisher and hitting it against the window. The impact resounded through the car, but the glass holds firm. “Not yet,” I begged under my breath, as the extinguisher bounced harmlessly away.

The water kept rising, and so did my fear. A voice inside me screamed to give up, but another thought pierced through — Stormy. “For Stormy, I can’t quit.” Just then, I sensed a pause in the water’s rise.

An unspoken sound said, “You have more time. What will you do?”

“I’ll fight harder,” I promised aloud.

Exhausted, we caught the now flooded vehicle, waiting for daylight.

6 . On June 23,2018,twelve young Thai boys and their assistant football coach wandered into a karst cave in northern Thailand, near the border with Myanmar. What happened next would grab the world’s attention and lead to a complex and daring international rescue operation. The 10.3-kilometer-long Tham Luang cave flooded, trapping the boys in total blackness nearly 2.5 kilometers from the cave entrance.

Thousands of people from around the globe participated in the rescue effort, including military personnel, medical experts and the rock stars of the operation — cave divers. The divers, who safely removed all of the Thai children and their coach after 18 days underground, dealt with tight spaces and low visibility in muddy water- conditions that would prove deadly: Saman Gunan, a former Thai Navy Seal, died while transporting air tanks into the cave.

While the sport of cave diving had received attention in the pop culture area prior to the rescue mission in North Thailand, there is little doubt that the brave divers at Tham Luang cave helped push the activity and its varieties of risks into global society’s minds.

The sport-often referred to as among the world’s most dangerous recreational activities-has its roots in pre-WWII England. Since then, the recreational practice of cave diving, described by Australian cave explorer Richard Harris (a participant in the Tham Luang cave rescue) as an “unusual hobby” for “the ordinary,” has spread around the world-China included.

Over 1,000 kilometers northeast of Tham Luang cave, in South China’s Guangxi Zhuang Autonomous Region, lies karst-peak-covered Du’an county-China’s little-known cave diving Mecca.

Home to thousands of kilometers of underground rivers, Du’an county offers divers spellbinding geological formations, perhaps the world’s largest collection of blind fish species and a rare variety of freshwater jellyfish.

10 . Scientists have created the first full-sized digital model of the Titanic. The model will allow scientists to study the Titanic in ways that have never been possible before.

The Titanic sank in the Atlantic Ocean in 1912. It was the largest ship of its time, and was thought to be unable to go down below the surface of water. But four days after it left Southampton, England, the Titanic hit an iceberg (冰山) and sank early the next day, killing some 1,500 people. The sinking is one of the most famous disasters in history.

The Titanic broke into two pieces, and sank to the sea floor, about 3.8 kilometers below the surface of the ocean. The location of the wreck (沉船) wasn’t discovered until 1985. Since then, many research teams have visited the site with undersea robots, whose trips have resulted in lots of pictures and videos of the wreck. But even these only allow scientists to study one area of the wreck at a time.     

Now, two companies — an undersea technology company called Magellan and the movie company Atlantic Productions — have created a 3-D model of the Titanic by sending two undersea robots down to the Titanic. The robots recorded both of the main pieces of the Titanic (the front and the back), as well as other hits of the wreck on the sea floor. Over six weeks, they took high-quality videos and over 715,000pictures, based on which scientists created the 3-D model of the Titanic. Using it, users will be able to see the ship from all angles.

The companies say the 3-D model will help scientists, enabling them to study the Titanic in great detail and study how the Titanic broke down, which could help them learn more about thousands of other shipwrecks also lying on the sea floor. And of course, scientists hope the model will help them better understand what happened when the Titanic sank.