三、阅读与回答问题
The 1970s marked the start of modern graffiti(涂鸦)in big US cities. In New York,young people wrote their names on walls around the city.
One of the first graffiti artists was a teenager named Demetrius. His tag(符号)was TAKI 183. It wasn't long before other teenagers started copying him,and soon there were tags on walls,buses and trains all over New York.
Later,some teenagers began to use spray paint(喷漆)to write their tags. During the 1970s and 1980s,tags became bigger and more colourful. Then the 1990s and 2000s saw the rise of graffiti artists. Some painted political statements,and others aimed to make cities more beautiful by painting large colourful pictures.
However,in some countries,this is a crime,which has led to some artists having problems with the police. In other countries,artists have been given space to paint freely. For example,in Bristol,UK,there is a yearly street art festival in August,where artists can paint all the buildings on a chosen street.
Slowly,the craft of street art is becoming more respected in today's art world,and some works are now on display at top art galleries in LA,London and Paris.
1. When did the modern graffiti in big US cities begin?
2. What was the tag of Demetrius?
3. What did some teenagers use spray paint for?
4. Do all the countries allow people to paint freely?
5. How is graffiti in today's art world?

1. The 1970s.
2. TAKI 183.
3. To write their tags.
4. No.
5. It is becoming more respected and some works are on display at top art galleries.