學英文 (求意見)

cherubic

I like "The Key Words" series of books published by Ladybird.  You may choose any level from 1 to 12 depending on the existing standard.  I guess level 3 may be the appropriate level for your kid.

This series is good particularly b and c books.  b book is story with a very good control of vocabulary.  The sentence structure is simple.  You can read with him regularly.

c book is phonics and simple compenhension.  You can ask him to do after reading corresponding b book.  

These books are cheap, only $30 each.
You may find more information from the ladybird website.