Question

providing (that),provided (that)和on condition (that)的用法

Answer 1

这几个连词用虚拟语气的较为普遍，但也要看具体情况。
1、
有时候表示事实相符的真实语气，如：
we
shall
go
provided
that
the
weather
is
fine
只要天晴,
我们就去。
suppose
he
can't
come,
who
will
do
the
work?
如果他不能前来,
谁来做这项工作呢?
i
will
lend
you
the
book
on
condition
that
you
return
it
on
monday.
如果说你能在星期一还我，我可以借给你这本书。
2、多数情况下表示与事实相反的虚拟语气，如：
provided
it
was
fine
we
would
have
a
pleasant
holiday.
如果天气好,
我们的假日真的有可能过得非常愉快（但是事实不是如此）。
supposing
your
father
saw
you
now,
what
would
you
say？退一步说你父亲现在看到了你,
你该怎么说？
i
will
go
abroad
on
condition
that
my
husband
goes
with
me,
but
he
said
he
wouldn’t.
如果我丈夫能和我一起去,
我就出国，但是他说他不愿意。
the
meeting
would
be
put
off
in
case
it
should
rain.
若遇下雨,
会议延期举行。

Answer 2

We can finish the job in time provided/on condition that there is a stable supply of material. 在材料供应稳定的前提下，我们能够按时完成任务。
provided that表示“在……的前提/条件下”，就是on condition that，其格式固定，不用providing that。