Which sentence would sound more natural? Are both of them grammatically correct? Which do you think is more correct?
See the example below for understanding how it works.
See the example below to understand how it works.
Learn English – “see the example below for understanding” versus “see the example below to understand”
infinitive-vs-gerundtransitivityverb-forms
Related Solutions
Although there are many people that claim that "none" and "neither" should always take the singular form, it's always sounded odd to me, so I decided to dig into it a bit further.
For example, here is an Ngram of "none of us is" / "none of us are":
In this case, we can clearly see that "none of us are" - i.e. the supposedly "ungrammatical" form of the sentence was vastly more popular until roughly 1880. In 1880 or so "none of us is" began to take hold, and in the 1920s there was a steep decline in the use of "none of us are" - perhaps in response to overzealous copy editors enforcing the so called rule.
Most interesting is what's happened since the 1990s, where "none of us are" has shot back to prominence, leading to the fact that "none of us are" is now the dominant form again.
As suggested by snailplane, here's some interesting additional reading which seems to confirm my opinion that "none/neither should take the singular" is a wholly invented rule:
http://johnemcintyre.blogspot.co.uk/2010/01/with-malice-toward-none.html
http://motivatedgrammar.wordpress.com/2009/01/08/none-is-none-are-grammar-according-to-clarkson/
As a native speaker, I've always just gone with choosing the verb as if "none" or "neither" was not taking part in the verb choice.
The sentences are too long. -> None of the sentences are too long
A or B is the correct answer -> Neither A nor B is the correct answer.
The first option is correct.
The reason for that is the second sentence is actually two gerunds nested inside of each other. Let me show you what I mean.
I love watching them play in the park.
The bolded text is the direct object of the sentence. "Watching them play" is a gerund phrase. "In the park" is just a prepositional phrase, and like most, it can be removed from the sentence without taking away anything from the grammatical structure or correctness. "I love watching them play." is also a valid sentence and a complete thought.
I love watching them playing in the park.
"Playing in the park" (or I suppose more technically just "playing") is a gerund phrase on its own, apart from "watching them". So what you are effectively saying is "I love watching them [noun]." As you probably know, nouns cannot be used as verbs.
I love watching playing children.
This is a correct sentence because "playing" is a participle used to describe "children," but it is a little awkward to say so you will not likely hear or see it in normal conversation. A more common version would be "I love watching children at play." I just wanted to play devil's advocate and show you what it would take to make a valid sentence with both "watching" and "playing" in the sentence, while preserving the meaning.
Best Answer
"to understand" is the preferred usage in your example.
In Hakan's comment, as well, the first example, "I'm sorry to bother you" is correct, however the second "I'm sorry for bother" is not. "I'm sorry for bothering you" would actually be acceptable, however, in the present (as I'm doing it right now). If you bothered someone in the past and are sorry, it would be "I'm sorry for having bothered you" ..
When to use to or for is difficult and usually better just to learn which places to use each, rather than trying to make sense of the rules. I'm a native speaker of English, and teach ESL, and I can't even tell you the rule off the top of my head.