subjective with doubt, disbelief and denial

Question

1. Creo que ellos ( jugar) al futbol.

2. No Hiego que ustedes ( estudiar )

3. Es obvio que Luis (aburrirse)

so confused on how to conjugate these - I have ten but these first three should give me direction on how to do this.

Answer 1

1. When "creer" is NOT negatative or interrogative, the Present Indicative is usual = juegan

2. Must be "niego?" = when you do NOT deny it, it implies it is true = estudian

3. It's obvious, so no doubt, no uncertainty, no Subjunctive! se aburre.

None of those 3 used the Subjunctive for the reasons above.

Sra

P.S. Now that you have met the Subjunctive you must decide if it is FACT = Present Indicative of Spanish I or DOUBT = Subjunctive.