Mr. Smith is busy these days ________ a new book on how to develop a child’s reading skill.

Mr. Smith is busy these days ________ a new book on how to develop a child’s reading skill.

1. A.
   working out
2. B.
   working on
3. C.
   working for
4. D.
   working with

Mr. Smith is busy these days ________ a new book on how to develop a child’s reading skill.

A. working out     B. working on     C. working for           D. working with

Mr. Smith is busy these days ________ a new book on how to develop a child’s reading skill.