English Grammar – Spot the Error (choose the segment with the mistake; if there is no mistake, choose ‘‘No error’’). Sentence: “This book is designed to increase a working knowledge of spoken and written English.”

Introduction / Context:The test here is idiomatic determiners with “working knowledge”. Books typically address “your” or “the reader’s” working knowledge. The phrase “increase a working knowledge” is odd because “a” does not anchor whose knowledge is being increased; the sentence needs a possessive or a definite reference to sound natural and precise.

Given Data / Assumptions:

• Purpose clause: “designed to increase …”.
• Target noun phrase in C: “a working knowledge of …”.
• Audience is general readers, so a second-person implied possessive is standard in educational copy.

Concept / Approach:

• Preferred collocation: “increase your working knowledge of …” or “increase the reader’s working knowledge of …”.
• Using bare “a working knowledge” without a possessor makes the claim grammatically awkward.

Step-by-Step Solution:

Verification / Alternative check:

Why Other Options Are Wrong:

Common Pitfalls:

Final Answer: