School papers, Essays, Dissertations/The difference

Advertisement


Question
Hi
Something in English I cannot understand fully is the difference between COULDN'T HAVE +PAST PARTICIPLE and MUSTN'T HAVE + PAST PARTICIPLE.

Could you please explain the difference?

Thank you so much
Best
David

Answer
Dear David,

I can explain the difference. "Couldn't have" indicates an impossibility that (often) has occurred in the past, while "mustn't have" indicates a highly probable unlikely event that (sometimes) has occurred in the past.

Let's say the sentence is, "He couldn't have committed the murder because he was in Paris that night." This means it is impossible that the person could be a suspect, whereas "He mustn't have committed the murder because he was in Paris that night" indicates that the subject is highly unlikely to be a suspect, but MIGHT have been a suspect; it leaves a very narrow margin of question, "might" representing that narrow margin.

However, to move it to present tense, if I say, "I mustn't have that dessert; I'll have to turn it down," I mean "I won't allow myself to eat it." If I say, "I couldn't have that dessert," the meaning is the same, and though this phrasing is used once in a while, the structure is incorrect -- it isn't "correct" to say "I could not have" something in the present, because "couldn't have," even in this context, most often refers to an event in the past.

I hope this helps!

All the best,
Catherine Van Herrin

School papers, Essays, Dissertations

All Answers


Answers by Expert:


Ask Experts

Volunteer


Catherine Van Herrin

Expertise

I can correct essays/papers up to 300 words.

If you want to see editor's marks, send the work to my email address (ceg33@myway.com), and I will return it in a Word document so you can see comments, suggestions, and explanations via Tracking Changes.

For further work or larger projects, see my profile here, with 190 excellent reviews: WordChannel Professional Reviews, Ratings

I can proof and edit graphs, tables, bibliographies, footnotes, indices, and references, but I do NOT format or arrange these.

I am a full-time freelance editor specializing in work for ESL (English as a second language) authors. I also work with native English-speaking authors in all areas.

I can answer questions related to grammar, style, tense, mood, consistency, flow, logic, accuracy, and spelling. If I can help you further, contact me at the website above (create a job request) or write to me at ceg33@myway.com to express your needs; I would be pleased to help you. My rate is $0.008 per word, and I process all payments through PayPal.

Experience

I am a native English speaker with a BA in English and more than 26 years of professional editing, writing, copy editing, fact-checking, and proofreading experience. Though I specialize in academic articles for ESL professionals and students, I also work with native English writers in any genre (fiction, non-fiction, children's books, website copy, etc.)

AREAS OF SPECIALIZATION: Editing ESL drafts, abstracts, CVs/resumes, and articles in the fields of medicine, science and economics (others as well; please inquire).

I have volunteered on AllExperts in the "Writing Books" category for several years:

http://www.allexperts.com/ep/675-80795/Writing-Books/Catherine-Van-Herrin.htm

I can use British-English or American-English and am proficient in Chicago and AP style, as well as various styles required for peer review and professional trade publications.

If I am unavailable here, you can reach me at ceg33@myway.com



Organizations
Editorial Freelancers' Association.

Education/Credentials
AA, Liberal Arts, Anderson College, Anderson, South Carolina. BA, English, University of Georgia, Athens, Georgia. Post-graduate study, Angelo State University, San Angelo, Texas.

Past/Present Clients
I have worked with many authors in the UK and America in many industries, but I have specialized in working with ESL clients from Germany, China, Finland, Spain, Russia, France, Portugal, Japan, Singapore, the Netherlands, Sweden, Switzerland, New Zealand, South Korea, the UAE, Italy, Australia, and Canada. References available on request.

©2016 About.com. All rights reserved.