It is Subjunctive. Conditionals use "If"
Ccording to the MLA Handbook, when you cite a source in the text of your paper, the citation should interrupt the text as little as possible; you want to lead the reader to the correct long-form citation in your Works Cited page with a minimum of fuss (116). There are two ways to do this - with a signal phrase, meaning the in-text citation will have only the page number(s), or with a parenthetical citation, meaning the in-text citation will include the author's last name (or the title, for an authorless work) and the page number(s) (Howard 289).
Signal Phrase
Format: Signal phrase, "quote" or paraphrase (page number).
The first sentence of the first paragraph on this page contains a signal phrase - "According to the MLA Handbook..." - with a page number in parentheses at the end of the sentence. The signal phrase lets your reader know that you are paraphrasing or quoting an idea from someone else's work. If your paper deals with a particular work of literature, or if you are relying heavily on the work of one or more sources, a signal phrase introducing the source is recommended.
Note that if you are quoting a source, in-text citation always comes after the closing quotation mark.
Examples of a Signal Phrase
In her work Pride and Prejudice, Austen makes the famous observation that "it is a truth universally acknowledged, that a single man in possession of a good fortune must be in want of a wife" (3).
Duhigg argues that we can change our habits, but because they are deeply ingrained into the brain, it can be a struggle to do so (20).
A line could be considered as a complete sentence if it both contains subject, verbs or predicate that make the whole idea in the line complete.
A Doctor (subject) + has Invented (verb) + a New Surgical Tool
So the line above could be considered as a complete sentence.
