Function words are a crux faced by the foreigners in Chinese language learning  because  65%  of  their  grammatical  mistakes  occur  in  the  use of  function  words.  Based  on  the  theories  of  SLA  and  from  the  learners’perspective focusing on their learning difficulties, this book attempts to help students  understand  and  acquire  the  meaning  and  usages  of  Chinese function words through explanations and exercises on those most commonly and easily misused function words so as to raise the learner’s ability to use the function words. With the help of formulas and forms, the explanation in this book is concise easy to understand and remember. The before-class, in- class and after-class exercises deepen the learner’s understanding through practice. The exercises are full in forms, and most of them follow the HSK model. Three comprehensive test papers with time requirement and answers and explanations to the exercises are attached at the back of the book, which facilitate self study and self test.