请将下面这段话翻译成英文：
国画是中国文化遗产的重要组成部分。不同于西方画，它是用毛笔(Chinese brush)和墨汁在宣纸(xuan paper)上作画的。精通这门艺术需要不断重复的练习， 需要控制好毛笔，需要对宣纸和墨汁有一定的认识。绘画前，画家必须在脑海里有一个草图并根据他的想象力和经验进行绘画。许多中国画家既是诗人，又是书法家。他们经常会在自己的画上亲手添加诗作。
参考翻译:
Chinese painting is an important part of the country's cultural heritage. It distinguishes itself from Western painting in that it is drawn on xuan paper with the Chinese brush and Chinese ink. To attain proficiency in this art, it is necessary to have a good control of the brush, and certain knowledge of xuan paper and Chinese ink besides repeated exercises.Before painting, the painter must have a draft in his mind and draw according to his imagination and experience.Many a Chinese painter is at the same time a poet and calligrapher who often adds a poem with his own hand on the painting.
1.不同于西方画，它是用毛笔和墨汁在宣纸上作画的:“不同于”可译为distinguish oneself from sth.,也可用be different from 表示。“毛笔和墨汁”可译为the Chinese brush and Chinese ink,此处可同用一个冠词表示整体；“用”可用介词with，表示方式。
2.精通这门艺术需要不断重复的练习，需要控制好毛笔，需要对宣纸和墨汁有一定的认识:“精通这门艺术”可译为to attain proficiency in this art，attain意为“获得、获取”，proficiency意为“精通、熟练”。“需要控制好毛笔，需要对宣纸和墨汁有一定的认识”，该句可理解为“控制好毛笔和认识宣纸、墨汁也是必要的”。
