____ is impossible to learn a foreign language well in such a short time ,Rome was not built in oneday.A.This B.It C.That D.Which

____ is impossible to learn a foreign language well in such a short time ,Rome was not built in oneday.A.This B.It C.That D.Which
____ is impossible to learn a foreign language well in such a short time ,Rome was not built in one
day.
A.This B.It C.That D.Which

____ is impossible to learn a foreign language well in such a short time ,Rome was not built in oneday.A.This B.It C.That D.Which
it.B
这是一个形式主语,所以用it开头

b