I have no idea what he likes.

In the upper sentence, there is no preposition in between "idea" and "what". I wonder the reason why this is.

I already checked out other questions similar to this one, but there was no reason explained for this. All answers say that it is just the way it is. But could you give me any proper guess for this?

Thank you.

1 Answer 1


The "compound verb" here is to have no idea. The syntax is exactly the same with many other verbs - for example, I know what he likes, I cook what he likes, I don't care what he likes.

Note that in some contexts with some verbs, the preposition about can be introduced. Sometimes this simply isn't possible (I cook about what he likes doesn't make much sense). But in other contexts, including about may subtly affect the meaning. Thus...

1: I know what he wants
2: I know about what he wants

...where (1) may simply mean I can identify what he wants. Perhaps we're in an Indian restaurant, and I'm about to tell the waiter that I know my friend wants a Bombay Duck as an appetiser (I may not know anything else about exactly what a Bombay Duck is, but I know that's what he wants).

Note that (2) above is idiomatically unlikely in most contexts, but one that you might encounter occurs in contexts like...

"Shall we go on a boat trip, or sunbathe on the beach? John wants to sunbathe"
3: "Yeah, yeah! We know [all] about what John wants! He just wants to ogle girls in bikinis!"

Even in (3), most people probably wouldn't include [all] about. But at least it doesn't sound "odd".

  • This topic (optional preposition use) seems to come up a lot. Is there a grammar rule that covers it?
    – user3169
    Mar 7, 2016 at 18:13
  • A "grammar rule"??? I think you're being a bit optimistic there! :) English uses prepositions a lot to make subtle (or "unsubtle") distinctions, but trying to explain all the different ways we do this would fill several books (and still only scratch the surface). There might be a few principles that apply in enough contexts to be be worth learners knowing about, but there are a lot more that don't really fit into any recognizable pattern. Mar 7, 2016 at 18:22
  • ...bear in mind that most native speakers have almost no conscious knowledge of such matters (we're not usually taught much about it in school; we just learn by copying others). Mar 7, 2016 at 18:24
  • Thanks. I wasn't aware of such a rule either, it is just what we learned to say. But a rule would make this easier to explain, rather than "sometimes people drop the preposition".
    – user3169
    Mar 7, 2016 at 18:35
  • Well, in the specific example presented by OP here it doesn't make much sense to talk about dropping the preposition, since normally there's no reason why we'd even have a preposition that might be dropped. It would be out-and-out ungrammatical to drop of when saying you're not aware of something. As explained, you can discard it in don't know [of, about] something - but again, it's not really just a "meaningless" optional choice. As usual, the precise phrasing adopted usually carries at least some nuance of difference. Mar 7, 2016 at 19:06

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