What does indicative, subjunctive and imperative mean?
Those terms are moods of verbs:
Indicative sentence is a sentence which informs about some facts.
John did not go to work because he was ill.
Subjunctive sentence is a sentence telling about assumptions and hypothetical situations.
If I won in a lottery, I would buy a new car.
Imperative sentence means giving someone orders or commands:
Do not lie to me.