The workbooks that comprise 'Modern English, 2nd Edition' are intended for high intermediate to advanced adult students of English as a second language. Based on the reference book, Modern English : A Practical Reference Guide, the workbooks provide carefully controlled exercises in a logically built up sequence form parts of speech (Part1) to complex structures (PartII)
There are abundant exercises on specific points of usages, with clear, concise explanations so that students can see the point of the exercise immediately.
It is not fair to call it a weak grammar book as I did gain some knowledge on some points that any person holding a bachelor's degree in English language must know. However, out of context sentences and exercises hardly make this book a good resource for learning PRACTICAL grammatical knowledge.