to verb vs verb
I always wonder if there is difference between "to + verb" and "verb". For example,
"It is not only to deepen students’ understanding of positive values, but also to enable them to know how to uphold positive values."
vs
"It not only deepens students’ understanding of positive values, but also enables them to know how to uphold positive values."
Is there any difference between the two structures?
Your first example (with the infinitive) expresses purpose. Whatever "it" is, its intended purpose is to deepen understanding and teach positive values.
Your second example (with the finite verb form) make a declaration. Whatever "it" is and whatever purpose anyone had for "it," what happened was a deepening of understanding and a teaching of positive values.
Answer
They are completely different.
Explanation
1.
A. "It not only deepens students’ understanding of positive values, but also enables them to know how to uphold positive values."
Let us extract the bare structure of this sentence:
It [not only] deepens [students’] understanding [of positive values], but [also] enables them [to know how to uphold positive values].
It deepens understanding, but enables them.
That looks a little odd so we can separate it into two sentences.
It enables understanding. It enables them. (i.e, the students)
2.
B. "It is not only to deepen students’ understanding of positive values, but also to enable them to know how to uphold positive values."
Now let's extract the structure from that sentence.
"It is [not only] to deepen [students’] understanding [of positive values], but to enable them [to know how to uphold positive values.]"
It is to deepen understanding. It is to enable them.
3.
We can see that all we really need to understand is the difference between:
a. It enables them.
and
b. It is to enable them.
Sentence a is very straightforward ---> (subject) (verb) (object)
4.
Sentence b is not so obvious and is the one that requires explanation.
The sentence, It is to enable them., can be parsed in only one way in English, and that is as an example of future obligation.
When we write about future obligations, we can use a formal pattern composed of two elements the verb to be in the present tense conjugated to match the subject + the infinitive of the main verb
http://www.edufind.com/english-grammar/future-obligation/
It is to enable them. means It must enable them.
5.
The analysis so far tells us that:
A. "It is not only to deepen students’ understanding of positive values, but also to enable them to know how to uphold positive values."
means
"It must not only deepen students’ understanding of positive values, but also must enable them to know how to uphold positive values."
That meaning is quite different from the meaning of sentence B.
6.
Now, I am well aware that in your initial question, you intended A and B to have the same meaning. I have shown that they don't. What can be done about it?
In fact there is no way to make A equivalent to B, they are essentially different.
What I can offer is an approximation. We add another grammatical element.
C. "It's purpose is not only to deepen students’ understanding of positive values, but also to enable them to know how to uphold positive values."
I hope this helps.