阅读下面短文,在空白处填入1个适当的单词或括号内单词的正确形式。
Paper-cutting is one of the most popular Chinese art 36 (form). It is popular for its low cost in all kinds of celebrations. What's more, it conveys the essence of 37 (tradition) culture through its unique artistic language.
Chinese paper-cutting is an art dating back 38 the 6th century. By the 7th century, it had become popular especially during Chinese festivals. The art 39 (introduce) to the rest of the world in the 14th century. In the countryside, paper-cutting was traditionally a handicraft passed down through generations. Local people 40 (learn) and practiced it from an early age.
Paper-cuts were traditionally used in various celebrations and ceremonies. Early paper-cuts featured patterns like flowers, birds and animals, 41 stood for good luck, blessings and protection. Today, paper-cuts are still 42 (wide) used as festive decorations. Meanwhile, they have taken on new forms, 43 (appear) in art exhibitions, interior design, book illustrations and even fashion.
44 is easy to learn the basics of paper-cutting, but difficult to master the craft. This art requires plenty of effort, constant practice 45 rich imagination.

36. forms 考查名词复数。此处为one of+the+形容词最高级+名词复数。故填forms。
37. traditional 考查词性转换。此处修饰名词culture，应当用形容词形式traditional。故填traditional。
38. to 考查介词。短语date back to表示“追溯到”。故填to。
39. was introduced 考查动词的时态、语态和主谓一致。主语art与谓语构成被动关系，根据后文in the 14th century可知，为一般过去时的被动语态，主语为单数。故填was introduced。
40. learnt/learned 考查动词的时态。根据上下文可知，本句描述过去的情况。故填learnt/learned。
41. which 考查定语从句。空处引导非限制性定语从句，修饰先行词patterns，空处在从句中作主语。故填which。
42. widely 考查副词。修饰动词used应用副词形式，故填widely。
43. appearing 考查非谓语动词。空处和后面的部分是对new forms的补充说明，在句中作状语，且they与appear是主动关系，应用动词-ing形式。故填appearing。
44. It 考查it的用法。此处为“it be+形容词+to do sth”句型，it作形式主语，动词不定式是真正的主语，句首单词首字母大写。故填It。
45. and 考查连词。结合前后文语境可知，effort，practice与imagination为并列关系，应用连词and。故填and。