Which one should I choose?

Look at the sentences below and see if you can decide whether of, have or ‘ve is standard.

1. I must of dropped my diary at home.
2. It was important that they should have completed the task on time.
3. He was afraid‘ve spiders making webs above his bed.
4. They left the goldfish in school by mistake during the summer holiday and it died of hunger.
5. ‘Why do you think they‘ve invited us over tonight?’ Jill asked suddenly.

The answers are at the bottom of the page – if you identified the standard usage correctly, you probably don’t need to read the rest of the page!

If you’re not so sure … read on …

How can I avoid slipping up?

The key lies in deciding what job of (preposition), have/‘ve (verbs) are doing. You need to look at the words that come before and afterwards. 

Remember these three rules:

1. if there is a modal verb (must, could, should, would, might etc.) in front and an -ed participle following, you need to put a verb in between (have or the shortened form ‘ve)
2. if there is noun or a pronoun in front and an -ed participle following, you need to put a verb in between (have or the shortened form ‘ve)
3. if there is an adjective, or a single verb followed by a noun or adjective, you need to use the preposition of

What makes it difficult is that of and ‘ve sound very similar in speech. The important thing therefore is to decide whether you need a verb (have or ‘ve) or a preposition (of). 

In your own writing or speech, you need to ask yourself the following questions:

• do I need a verb because there is an -ed participle? → if the answer is YES, choose have in formal writing and speech, or ‘ve in an informal context
  
• do I need a preposition to link an adjective or verb to additional information? → if the answer is YES,  choose of

ANSWERS

The standard usage is in blue. Non-standard usage is crossed through – the standard version is in red.

1. I must of dropped my diary at home. [modal verb must + -ed participle = verb have (formal) or the contracted ‘ve (informal) → not preposition]
2. It was important that they should have completed the task on time. [modal verb should + -ed participle  = verb have  (formal)] 
3. He was afraid‘ve spiders making webs above his bed. [adjective + of to link additional information → not contracted form of verb have]
4. They left the goldfish in school by mistake during the summer holiday and it died of hunger. [verb + preposition of to express ‘how’ → of = ‘because of’]
5. ‘Why do you think they‘ve invited us over tonight?’ Jill asked suddenly. [contracted form of have + -ed participle  (informal speech)]