I have been coming across this kind of sentence more and more:

She gave him a key to enable him to escape capture.
She gave him a key to enable him escape capture.

Which sentence is correct? My understanding is that the preposition should be repeated as both enable and escape are verbs.

  • 1
    It depends on what verb is used; with enable as in your example above, I would say the "to" is required. If you use "help" instead, I would say that it is not. I don't know off the top of my head why this is, but it may have something to do theta roles.
    – rintaun
    Jun 29, 2011 at 10:38

2 Answers 2


"To" isn't a preposition here, it's part of the verb. Sentences like this generally use the full infinitive (or to- infinitive) to introduce the subordinate clause. Like I just did there.

She enabled him to escape capture.
She helped him to choose a new wardrobe.
She told him to go away.

Help turns out to be able to use a bare infinitive instead:

She helped him choose a new wardrobe.

but not

She enabled him escape capture.

With some verbs, you must use the bare infinitive. Mostly these are verbs concerning perception or permission; unfortunately you just have to know which ones are which.

She saw him run away.
She let him go.


She allowed him to go.
She observed him to run away. (This particular one is very unusual, and I wouldn't use it if I didn't have to!)

  • +1, and that's pretty much the story. I only add that She observed him to run away would be understood as She observed him [in order] to run away, i.e. that her observation was a necessary prerequisite to her having the ability to run away.
    – Robusto
    Jun 29, 2011 at 12:36
  • There is a list of different verbs that catenate, the grammatical form(/s) they require, and whether or not the subject governs both verbs semantically at courses.washington.edu/englhtml/engl371/catenatives.html . Dec 19, 2012 at 19:30

Does this seem OK? Or is the second 'to' redundant? Thanks a lot.

Management will provide substantial levels of support, such as resources and training, to enable the museum staff to provide a quality guiding service.

  • Some might ask themselves: is this an answer or a question? Suggest edit to make it more clear that you're being rhetorical (if that is indeed what you're doing) Oct 8, 2015 at 1:12

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