I´m afraid I can´t give you a definite reply now. 恐怕我现在无法给你一个明确的答复。

I can´t make a decision right now. 我现在无法作出决定。

I just need some time to think it over. 我需要时间考虑考虑。

We are still a little unsure about the prospect, though. 不过，我们对于前景还是有点不能确定。

There are certain points that I´ll have to consider very carefully. 有些问题我得慎重考虑。

That may well be so. I´m not sure. 很可能是这样的。我不敢确定。

It all depends. 这得看情况而定。