18. Interchange book
Interchange is a four-level, American English course that has been used by over 50
million students worldwide. This Intro Level Student's Book A includes units 1-8,
four progress checks, and a Grammar Plus section to ensure that students receive
all of the practice they need.
Inside each book is a single-use code for online self-study material. This gives
access to videos and hundreds of automatically graded exercises, and works on
PCs and Macs. Also included is a single-use code for the Online Workbook, which
contains even more practice, as well as games.