Breakdown of Esta bomba está a punto de explotar.
de
from / of
estar
to be (location/state)
a
to
el punto
dot / point
Questions & Answers about Esta bomba está a punto de explotar.
How does estar a punto de work in this sentence?
The phrase estar a punto de is a fixed expression meaning 'to be about to' do something. It literally translates as 'to be at the point of'. It is a proximity periphrasis that must always be followed by an infinitive verb, which here is explotar (to explode).
Why are there two almost identical words, esta and está, at the start of the sentence?
They look similar but are completely different words. The first, esta (no written accent, stressed on the first syllable), is a demonstrative adjective that means 'this' and describes the feminine noun bomba. The second, está (with a written accent, stressed on the last syllable), is the verb 'is'.
Could I say es a punto de instead?
No, you must always use estar with this expression. Being 'about to' do something describes a temporary state or condition in a specific moment, which perfectly fits the general rule for using estar over ser.
Why is explotar left in its infinitive form?
In Spanish, when a verb immediately follows a preposition like de, it must stay in its unconjugated infinitive form (the base form ending in -ar, -er, or -ir).