Watch the part of Characteristics of Chinese Painting and choose appropriate words in brackets to complete the following passage.The brush pen has a long history in China. In the beginning, people wrote on bamboo slips. Around the time of the Warring States Period, ancient Chinese started to tie 1) ____________ (rabbit / wolf) hair to bamboo sticks to make a brush pen. The brushes of the early period were 2) ____________ (rough / crude) and simple; later the 3) ____________ (structure / texture) of the brushes improved in various ways.Chinese painting is also known as ink and 4) ____________ (wash / water) painting, so we can see the importance of ink. In Chinese painting, five shades of ink are 5) ____________ (focused / emphasized) by painters. It is the amount of water mixed with ink, the rhythm of 6) ____________ (brush / pen) and the length of strokes that produce various styles of paintings. In the ancient time, the artist has to 7) ____________ (grind / rub) the ink stick on an ink slab with water, which is not so convenient compared to the modern ink. Though the modern ink is much more convenient, most contemporary artists still use the ink stick in painting.Paper is one of the most basic 8) ____________ (equipment / tools) of Chinese painting. Chinese painters use Xuan paper, which was originally produced during the Tang Dynasty. It was named after the place where it was produced, Xuanzhou in today's Anhui Province. Xuan paper absorbs ink well and shows clearly the lines and strokes. It has great tensile 9) ____________ (power / strength) and is hard to be creased and corroded. It has been widely used in Chinese calligraphy and painting for many years.The Ink slab is a tool to grind the ink stick. Ink slabs come in various shapes and can be made of various materials such as stone, pottery, brick, jade, etc. A fine ink slab will greatly and positively affect the ink color and can 10) ____________ (keep / preserve) the ink for a long time.