# Which one to use in an enumeration, to-infinitives, bare infinitives, or gerunds?

I am writing a summary paper about a report I read with this sentence in it:

This report follows two steps: determine the population density increase and analyze the productivity growth influenced by the population density increase.

I feel uncertain about whether to use bare infinitives or gerunds. I know it is idiomatic to say

All you need to do is go up and ask them.

But can you say it using the gerund or the to-infinitive?

All we need to do now is getting this job done
All we need to do now is to get this job done

What about sentences about events in the past? Can the past tense be used?

There are two things she should've done: listening (listen? listened?) to her mother and going(go to? went to?) to college.

Going back to my sentence, is it correct with the bare infinitive and can it be written with the gerund or the to-infinitive?

This report follows two steps: determining (to determine?) the population density increase and analyzing (to analyze?) the productivity growth influenced by the population density increase.

Is using semicolons possible as well?

This report follows two steps: determine the population density increase; analyze the productivity growth influenced by the population density increase.

• Your use of conclude is very confusing. Do you mean you end your report by doing two things? Or do you mean that you present your findings (conclusions). I have come to the conclusion or I conclude that I do not understand your question. – Lambie Sep 11 '18 at 22:55
• @Lambie My writing is actually a summary of another piece (the report). Edited my question. – Eddie Kal Sep 11 '18 at 22:58
• Please answer my question. What do you mean by: come to its conclusion? Do you mean its findings?? Or its end? – Lambie Sep 11 '18 at 23:01
• I meant to say that the report explains several steps it takes to reach its conclusion. I will get rid of the word conclude/conclusion if it makes the sentence clearer. However, if whether the two steps are part of the conclusion makes a difference in choosing between the infinitive and the gerund, I would like to know that too. – Eddie Kal Sep 11 '18 at 23:09
• conclusion meaning findings,then. – Lambie Sep 11 '18 at 23:11

This report follows two steps: determining population density increase and analyzing productivity growth as affected by population density increase.

The colon basically replaces the preposition by or in. A gerund is needed since without it there would be a by or in which takes a gerund. It is an activity, therefore, a noun gerund. Also, you do not need a semi-colon as the structure is completely parallel.

Also, I removed two determiners: the

All we need to do is get the job done.

Compared to: Getting the job done [subject] is all we need to do.

The gerund versus bare infinitive here is grammar. You need the gerund here as the by or in preposition is removed and you are referring to an activity.

Determining population [a subject, a gerund] density increase is tricky.

An easy example:

They do the work BY determining population density.

They do the work: determining population density.