When Juliet was a 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 mum, she looked around and felt very unhappy. "What's the matter, dear?" asked her mum. Juliet replied, "Mum, there's so much trash on the ground." Juliet's mum looked around. There was paper, boxes and glass bottles everywhere. "What can we do?" asked Juliet. "I'm sure you will think of something," said her mum. As soon as Juliet and her mum 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 took plenty of bags and went back to the park with her mum. Juliet put up her picture on a big trash can  . "Will you help me pick up the trash, Mum?" Juliet said as she handed her mum a bag. "I sure will," replied her mum. 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 mum said, "So it does. _ " Which of the following is TRUE about the children?
They laughed at Juliet. They had an awful and tiring day. They bought some bags from Juliet. They joined Juliet in picking up the trash.