Final answer:
The infinitive in the given sentence is "to make sure." Infinitives are the base form of verbs, typically preceded by 'to,' and can serve as a noun, adverb, or adjective.
Step-by-step explanation:
The infinitive in the sentence, "Before Milestones testing begins, it is important to make sure all computer issues are corrected," is the phrase "to make sure." An infinitive is the base form of a verb usually preceded by the word 'to.' In this given sentence, the infinitive functions as a noun because it is the object of the preposition 'to.' Infinitives can also function in different ways, such as adverbially, which modifies a verb, or adjectivally, which modifies a noun. Infinitive phrases can include other words or modifiers, and these are considered part of the infinitive phrase.
For example:
- To talk about poll numbers at this stage of the election is simply counterproductive.
- To ensure a full refund, you must also bring your receipt.
- A fistfight is no way to resolve an argument.
In these examples, the infinitives are 'to talk,' 'to ensure,' and 'to resolve,' showing the various functions of infinitive phrases within sentences.