Graffiti（涂鸦）

Street art is a very popular form of art that is spreading quickly（quick） all over the world. You can find it on buildings, sidewalks, street signs and dustbins in many big （41）_____（city） of the world. Street art has gained great（42）_____（popular）. Even art museums and galleries are（43）_____（collect） the works of street artists. Street art started out very（44）_____（secret） because it is illegal to paint public and private property without permission. People often have different（45）_____（opinion） about street art. Some think it is a crime and others think it is a very（46）_____（beauty） new form of culture.

Art experts claim that the（47）_____（move） began in New York City in the 1960s. Young adults（48）_____（spray） words and other images on walls and trains. This（49）_____（color）, energetic style of writing became（50）_____（know） as graffiti.