SF Express is really fast. The book is an internal teaching material. The cover design is good and the content is basic. It is suitable for a novice like me to learn. SF Express is really fast. The book is an internal teaching material. The cover design is good and the content is basic. It is suitable for a novice like me to learn. SF Express is really fast. The book is an internal teaching material. The cover design is good and the content is basic. It is suitable for a novice like me to learn. SF Express is really fast. The book is an internal teaching material. The cover design is good and the content is basic. It is suitable for a novice like me to learn. SF Express is really fast. The book is an internal teaching material. The cover design is good and the content is basic. It is suitable for a novice like me to learn.