I’m guessing you mean the sentence passive? but it would be “the water boiled at 100°C” if so.
I believe there are no prepositions in this sentence, here is an example of a few prepositional words:
about
below
excepting
off
toward
above
beneath
for
on
under
across
beside(s)
from
onto
underneath
after
between
in
out
until
against
beyond
in front of
outside
up
along
but
inside
over
upon
among
by
in spite of
past
up to
around
concerning
instead of
regarding
with
at
despite
into
since
within
because of
down
like
through
without
before
during
near
throughout
with regard to
behind
except
of
Hi!
I think it is the first one, because you can tell he is afraid.
Hope this helps!
