necessary
to
complete
the
design
before
National
Day?
a.this
b.that
c.it
d.he
C should be chosen in this question, and the other items are disturbing to some extent. This paper mainly investigates the usage of the formal subject it
. Generally speaking, when the subject is a complex component (such as infinitive, gerund, clause, etc.), the formal subject it is usually used at the beginning of the sentence, and the real subject is put behind:
is
it
necessary
to
tell
his
father
everything. Is it necessary to tell his father all this?
it
is
wrong
to
say
anything
like
that
on
that
occupation. It is wrong to say that on that occasion.
it's
no
good
sitting
up
too
late. It's no good staying up late.
it'll
be
wonderful
lying
on
the
beach
all
day. How wonderful it would be to lie on the beach all day!
it
is
quit
clear
that
he
has
read
the
book. Obviously, he has read this book.
it's
a
problem
where
we
could
get
so
much
money
. It's a difficult problem where we can get so much money.
sometimes the preposition for/of
can be added before the infinitive used as the subject:
it
is
very
kind
of
you
to
say
that. It's very kind of you to say so. It
is
important
for
us
to
keep
the
balance
of
nature. It is very important for us to keep the ecological balance.