I am confused sometimes if I should add " about/ as to" before wh words, sometimes not.

Which one do you think correct is?

Do you have a suggestion about/ as to which book I should buy ?

Do you have a suggestion which book I should buy ?

I don't want to change whole question because I have already some answers.But I need to say that this question has nothing to with the word suggest.

My question is that when to use as to/ about/ regarding in a sentence.

  • Seems like "about" or "as to" if preceding "which book" are mostly filler words. They are not needed. Without them (the second form) the question is just as good. Oct 9, 2015 at 20:14
  • The verb suggest and the verb-phrase make a suggestion are driving your question, Mrt, even though you think you're asking about about.
    – TimR
    Mar 25, 2016 at 18:01

4 Answers 4


(My answer have some limitations, because I myself can't answer beyond that, but without going there if you read my answer you will probably get the answer of your question, not too deep though.)

Do you have [Noun Phrase (NP)]?

Now this NP here is -

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Here the PP (prepositional phrase) is the complement of the head noun (suggestion). A PP often acts as a complement or postmodifier of a noun phrase.

The prepositional phrase structure is like this -

enter image description here

There has to be a head preposition - as to/about. Without it the phrase structure is incorrect. And the complement to the head preposition is an embedded wh question.

So from it, it's clear that you can't omit as to or about from the sentence, or it will make it ungrammatical.

Without the preposition there is no connection between the head noun and which book I should buy part. A preposition connects them together.

(My answer doesn't address why the complement to the head noun in the NP tree has to be a Prepositional Phrase. The simple answer is I don't know. I couldn't find the reason beyond what I said here in any grammar book I checked, though I haven't checked many books. I think this will be dealt with not in grammar books, but in good linguistic books, and I don't have any. Nor do I have any knowledge in linguistic theory. Someone else might answer it better.)


I am a native speaker of U.S. English.

Your second example is not a sentence form with which I am familiar and I don't believe it is well-constructed -- the first four words create a complete thought, as do the last five words. I believe they need something to connect them.

As an aside, there are parts of the U.S. where it seems optional to use the words 'to be' in almost any sentence. This leads to communication attempts such as this one:

My car needs fixed.

Your second example reminds me of that colloquialism. Upon first encountering it, I found it quite jarring and I would recommend avoiding them both.

I would personally use 'regarding' in this context, but both of your suggestions in your first example would be fine as well.

However, after considering the presumed situation where this sentence could prove valuable, I would most likely say:

Could you please suggest which book I should buy?

This seems, to me, to be the most natural form for eliciting a book suggestion from another.

  • So can I say that it would not sound natural if I said "Could you please suggest about/ as to which book I should buy? "
    – Mrt
    Oct 9, 2015 at 21:09
  • 1
    Yes, that would be wholly unnatural. ;-) You could say "...please make a suggestion as to which book..." or "...please suggest which book...". The second example is the more active form and would be the default for use in conversation. The first example is more passive and verbose. It is asking for the noun 'suggestion' and needs more information to determine what kind of suggestion is required. My second example asks for a verb, the action of 'suggest which book', which is more on point. Oct 9, 2015 at 21:50
  • Thank you, I will observe if we can use about after a noun mostly.
    – Mrt
    Oct 9, 2015 at 22:07
  • @MrW - I agree with your answer and your comment, with one small caveat: in conversation, we sometimes start speaking before we've completely formed our thought. So, walking into a bookstore in search of a good birthday present for my 5-year-old niece, I might start by saying, "Do you have a suggestion..." At this point, I don't slam on the brakes and start over with the active voice. Instead, I keep going, continuing with a preposition: "...for a good book for a 5-year-old girl?" In an email message, I'd probably rephrase that (as you did) before clicking SEND, but it's okay when talking.
    – J.R.
    Oct 11, 2015 at 11:00

The second example is incorrect.

In the first, either "about" or "as to" is idiomatic, but as a matter of style I prefer "about."

Better than either, though, is a complete rewrite:

  • Which book do you think I should buy?

  • Which book do you suggest I buy? (a bit formal)

  • Can you suggest a book for me to buy?


Many native speakers say things like:

Can you make a suggestion which hotel to stay at?

Do you have a suggestion what movie to see first?

The sentences are parsed without a hiccup by other native speakers as though the phrase "Can you make a suggestion" was interchangeable with "Can you suggest" and "Do you have a suggestion" with "Would you care to suggest".


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