A、Feelings and thoughts. B、Color and emotions. C、Color and shapes. D、Symbols and shapes. C在谈到抽象画时，短文提到这位艺术家运用色彩(color)和形状(shapes

Until the 20th century, most paintings were representational. This means that artists "represented" their subjects in a way that was realistic and recognizable. However, during the first half of the 20th century, artists like Jackson Pollock started to explore other methods of representation.
    When he first began painting, Jackson Pollock painted representational objects such as people and animals. However, he is famous for helping to create a whole new art movement called Abstract Expressionism. An "abstract" image is one where the subject is not represented realistically. Instead, the artist uses color and shapes to suggest the most general qualities of the subject. "Expressionism" is a kind of art that expresses feelings and thoughts. Abstract Expressionism is art that shows emotions and ideas through non-representational forms.
    In Pollock’s most famous works, there is no recognizable subject. His art works are large surfaces of canvas completely covered in different colors of paint. However, Pollock did not start out as a revolutionary painter. He developed the artistic process he became famous for over many years. Jackson Pollock was born in Cody, Wyoming in 1912. He grew up in the states of Arizona and California. Pollock later said that the wide-open land of these western areas greatly influenced his expansive artwork. In 1930 he moved east to New York City where he studied at the Art Students League. There, Pollock spent a few years studying with the artist Thomas Hart Benton who painted images of every day American life. Pollock’s early works are similar to his teacher’s kind of painting. However, Pollock slowly left this traditional art education behind.
16. Before the 20th century, how did artists represent subjects in their paintings?
17. What is Jackson Pollock well-known for?
18. What does Jackson Pollock use to represent an abstract image?
19. What can we learn about Jackson Pollock according to the passage?