Oxford Progressive English Readers (OUP)
The books in the Oxford Progressive English Readers (OPER) series are arranged in six levels: a Starter level and five progressively more advanced levels. The levels correspond approximately to the secondary school form designations. Text lengths increase at each level, from 8,000 words at the Starter level to about 35,000 words at Level 5. The hardest titles, at Level 5, are quite challenging, and a student who can read these texts reasonably well should, with a little help, soon be able to move on to unadapted English texts. Guidance on finding the right level is available as a download at http://www.oupchina.com.hk/elt/oper/about.asp
