Final answer:
The phrase 'Es seguro que...' is associated with the indicative mood, which is used for facts or truths. It is not subjunctive, which expresses doubts, wishes, or hypothetical situations. Examples of verb modifications include 'skies' and 'dries'.
Step-by-step explanation:
The phrase 'Es seguro que...' suggests certainty about the information that follows, which indicates that the indicative mood is the correct choice. The indicative mood in Spanish is used to talk about actions, events, or states that are believed to be facts or true. It aligns with stating a fact or an opinion. For example, 'Es seguro que lloverá mañana' translates to 'It is certain that it will rain tomorrow.' Here, the speaker is asserting something they believe to be true.
If you were looking for verbs that change when conjugated in the third person singular, here is how they are modified: 'sky' becomes skies, 'ally' becomes allies, 'dignify' becomes dignified, 'satisfy' becomes satisfied, 'modify' becomes modifies, 'terrify' becomes terrified, 'multiply' becomes multiplied, 'testify' becomes testifies, 'qualify' becomes qualified, and 'dry' becomes dries. Note the changes according to the rules of forming plurals or third person singulars in English, mostly involving adding 'es' or changing 'y' to 'ies'.