pushing buttons, experimenting, and building. When everyone is tired, enjoy a fun family science show, commonly found in these museums.

21.If a child is interested in the universe, he probably will visit .

A.a Youtheater B.an art museum

C.a natural history museum D.a hands-on science museum

22.What can kids do at a Youtheater?

A.Look at rock collections. B.See dinosaur models.

C.Watch puppet making. D.Give performances.

23.What does "hands-on science" mean in the last paragraph?

A.Science games designed by kids B.Learning science by doing things

C.A show of kids' science work D.Reading science books

　　A 15yearold boy planned to put a ball covered with petrol into his mouth and set it on fire. He would film the dangerous action and put it on YouTube. And, he hoped to become famous on the Internet. But things didn't go the way he imagined. His clothing caught fire, and he was rushed to the hospital with serious burns on his body.

　　YouTube hosts millions of videos of people attempting dangerous actions. Many of them are by kids and young adults. Some experts say that by hosting these videos, YouTube encourages young viewers to take deadly risks. Research by the Centers for Disease Control and Prevention shows that more than 180,000 Americans die from accidental injuries each year. That's one person every three minutes. More than 14,000 of those killed are kids under the age of 19. Is YouTube to blame?

　　People have always found it interesting to watch others try risky things. Audiences love these kinds of things. Some of the earliest Greek comedies had characters followed by wild animals and knocking into walls. Now, in the age of the Internet, anyone with a camera and a YouTube account can create this kind of "fun". Many viewers, especially teenagers, are influenced by what they see and want to try it themselves. "YouTube has taken the playing in the neighborhood to a worldwide level，"says Clair Mellenthin, a researcher from the Centers.

　　Supporters of YouTube argue that it isn't YouTube's responsibility to examine its content. "Parents should be the ones to make sure that kids are behaving safely，" they say. In fact, YouTube has a rule on content. For example, dangerous activities that have a risk of serious physical harm or death are not allowed. Staff of You Tube, carefully watch the website 24 hours a day, looking for videos that are against their rules. But is this enough?

24. What happened to the 15yearold boy?

A．He got burnt in a traffic accident. B．He played with fire and burned himself.

C．He set fire to a ball by accident. D．He watched an action film on YouTube.

25. What do Clair Mellenthin's words suggest?

A．YouTube should examine kids' accounts.

B．YouTube users like to copy Greek comedies.