For students who study Chinese as a foreign language, it's crucial for them to enlarge the scope of their reading to improve their comprehension skills. The "Rainbow Bridge" Graded Chinese Reader series is designed to provide a collection of interesting and useful Chinese reading materials. This series grades each volume by its vocabulary level and brings the learners into every scene through vivid storytelling. The series has the following features：

I. A gradual approach by grading the volumes based on vocabulary levels.
We have consulted the New HSK Vocabulary (2012 Revised Edition), the Graded Chinese Syllables, Characters and Words for the Application of Teaching Chinese to the Speakers of Other Languages (National Standard) and the 1,500 Commonly Used High Frequency Chinese Vocabulary, along with the Common European Framework of Reference for Languages (CEFR) to design the "Rainbow Bridge" vocabulary grading standard. The series is divided into seven levels (Starter*, Level 1, Level 2, Level 3, Level 4, Level 5 and Level 6) for students at different stages in their Chinese education to choose from. For each level, new words are no more than 20% of the vocabulary amount as specified in the corresponding HSK and CEFR levels. As the levels progress, the passage length will in turn increase. 

The following table indicates the corresponding "Rainbow Bridge" level.HSK and CEFR levels, the vocabulary amount, and number of characters.

Level	Starter	1	2	3	4	5	6
HSK    CEFR Level	HSK1   CEFR Level        A1	HSK1-2    CEFR Level       A1-A2	HSK2-3    CEFR Level        A2-B1	HSK3   CEFR Level         A2-B1	HSK3-4    CEFR Level         B1	HSK4    CEFR Level         B1-B2	HSK5   CEFR Level        B2-C1
Vocabulary	150	300	500	750	1000	1500	2500
Characters	1000	2500	5000	7500	10,000	15,000	25,000

2 Intriguing stories on various themes.

The series features engaging stories known for their twists and turns as well as deeply touching plots. The readers will find it a joyful experience to read the stories. The topics are selected from Chinese mythology, legends, folklore, literary classics, biographies of renowned people and historical tales. Such widely ranged topics would exert an invisible, yet formative, influence on readers' understanding of Chinese culture and history.

3 Reasonably structured and easy to use.

For each volume of the "Rainbow Bridge"series, apart from a Chinese story, they also provide an introduction to the main characters in Chinese and English, new words with English explanations and sample sentences ,and an English translation of the story .followed by comprehension exercises and a vocabulary list to help users read and understand the story and improve their Chinese reading skills. The exercises are mainly presented as objective questions that take on various forms with moderate difficulty. Moreover, keys to exercises are also provided.The series can be used by teachers in class or by students for self-study.