I was going to a supermarket when the fire _____________ (to break) out.
was breaking
broke
had been breaking
had broken
In this case the first action was in progress when suddenly something interrupted it. For a longer action we use the Past Continuous Tense. The second action was shorter so we should use the Past Simple Tense.
Well, I ___________ (to take) this pair of shoes.
am taking
take
am going to take
will take
We use the Future Simple Tense when we have no plan or decision before we speak. We make it at the time of speaking.
New Year __________________ (to celebrate) all over the world.
celebrates
is celebrated
celebrated
is celebrate
When we don't know who carries out the action, or it is obvious or unimportant to us, we use the Passive voice. The Passive is formed: BE + Past Participle