Final answer:
The Subjunctive Mood is used to express uncertainty or doubt. In the phrase 'Es dudoso que...', the verb following 'que' will be in the Subjunctive Mood.
Step-by-step explanation:
Subjunctive Mood is used to express wishes, suggestions, requirements, or to state hypothetical or unlikely situations. In the case of the phrase 'Es dudoso que...' (It is doubtful that...), the verb following 'que' will be in the Subjunctive Mood. It indicates uncertainty or doubt about the statement that follows.