What Juliet was child, she often went to the city park and played with her friends. On a sunny morning, when Juliet came to the park with her mom, she looked around and felt very unhappy.

“What’s the matter, dear? What’s wrong with you?” asked her mom.

Juliet replied, “Mom, how beautiful and clean it used to be! But now there’s so much trash on the ground.”

Juliet’s mom looked around. There were scraps (碎片) of paper, boxes, glass bottles and a lot of other trash everywhere.

“What can we do?” asked Juliet sadly.

“I’m sure you will think of something,” said her mom.

As soon as Juliet and her mom went home, Juliet painted a picture of the park and wrote a sign in large black letters at the top of the picture. The sign read “PLEASE KEEP OUR PARK CLEAN”. Later, she look plenty of bags and went back to the park with her mom. Juliet put up her picture on a big trash can (垃圾桶).

“Will you help me pick up the trash, mom?” Juliet said as she handed her mom a bag.

“I surely will,” replied her mom smilingly.

The children at the park ran over to see what was going on. Juliet handed them each a bag. “Let’s clean this place up,” said Juliet. Then they began to pick up the trash, talking and laughing. Soon all the bags were full.

“We need to come back another day. There’s still some trash on the ground, but the park looks much better,” said Juliet.

Her mom said, “So it does. I knew you would think of a way to help.”

Do you know what will happen in a weightless environment? Students attend a science lesson given by astronauts on board China’s Tiangong space station on Wednesday, March 23, 2022. Zhai Zhigang, Wang Yaping and Ye Guangfu, the members of the Shenzhou XIII, which was launched (发射) on October 16, appear on television screens watched by millions of students across China.

During the 41-minute lesson, the astronauts did four experiments to show physical phenomena (现象) only possible in a weightless environment, such as “liquid crystallization” and “a water bridge”. In one experiment, Wang used a toy of Bing Dwen Dwen, the mascot of the 2022 Beijing Winter Olympic Games, to show how objects fly in Tiangong. They invited the young viewers to do similar experiments to see the differences between space and land environments.

Before closing the lesson, the astronauts answered questions from students. The questions covered the life and work in space, such as how to take care of the skin and whether hot water was available. Wednesday’s event marked the third time Wang had taken part in a space lesson. In June 2013, she gave the nation’s first space lesson to over 60 million Chinese students in Shenzhou X. It made China the second country, following the United States, to have given a lesson to schoolchildren from space.

In early December, Wang gave the country’s second space lesson from the Tiangong station. The astronauts showed viewers how they lived and worked inside the space station.

“These science lessons can encourage students to explore the world of science and technology.” Shi Yi, a physics teacher, said after today’s activity, “Encouraged by China’s spaceflight achievements, my school has built a space science laboratory and the teachers give lessons about space exploration.”

Robbie looks out of the window. It’s still snowing heavily and there is ice on the window. It is another day. Robbie is told to do the cleaning. And he does it. The family are getting home.     16     All of the housework is easy for Robbie, but a hard one for its master, Helen. Robbie really saves the family a lot of work.

Mr. Green is a fourth grade robot teacher.     17     He even knows each child’s pets and hobbies. He has his lessons in an orderly way, and he never feels tired. The children like Mr.Green very much.     18     When they make a mistake, they don’t feel upset. They have a lot of fun with a robot teacher.

ASIMO is a clever robot created by the Honda Motor Company. He is about 120 centimeters tall and looks like a kid in a spacesuit. Tiny computers are used to control the things ASIMO can do. He can shake hands with people, give and receive objects. He can walk and run forward or backward on two legs.     19     When something is in his way, he can change directions.

Robots are smart because they have computer brains. Some of them have explored other planets.     20     For example, robots are used to make cars. People also use robots to do dangerous work such as exploring volcanoes (火山) or the ocean floor. Robots are also used to give directions in shopping centers and amusement parks.

Scientists keep finding more ways for robots to help us.