I am learning English grammar from a book. The current section I am learning is Adverbial clauses of time (future reference).The section says to use present form after adverbial clause when referring to future. e.g
The Owens will move to new flat when their baby is born.
We should visit the Duty Free Shop before our flight calls.
Now as we know called is the past form of call verb, So how can we say ...before our flight is called
.
like is it right to say e.g
The verdict was announced and Pierre is punished for a crime he is unaware of.
So my question is, can we use the past form like punished
or called
with is, as we see in the sentences: Pierre is punished
or flights is called.
Best Answer
As Khan tells you, the -ed forms you ask about are not being used as past-tense forms but as past participles.
With "regular" verbs, the past-tense and past-participle forms are the same. But many of the oldest verbs in the language follow different patterns, in which the past-participle form is marked with a change in the stem vowel or an -en ending, or both.
It is the past-participle form which combines with a form of BE to form the passive-voice construction. The participle itself has no tense; the time referred to is determined by the tense of the BE form:
The past-participle form also combines with a form of HAVE to form the perfect construction; and the perfect and passive may be combined with the past-participle form of BE:
All of these may also be cast into future tense with the modal auxiliary will or the BE going to construction. In this case the following auxiliary ('helping') verb, BE or HAVE, takes the infinitive form
There's rarely a need for the future perfect; I've seen an estimate that the future perfect passive occurs about once every 1800 printed pages!