难说的英文：
it's hard to say; no one can tell

参考例句：

Whether it will do us harm or good is hard to say .
这对我们是好是坏还很难说。

The plan's success was balanced on a knife-edge
计划能否成功还很难说。

It was touch-and-go whether we would get to the airport in time.
我们是否能按时到机场还很难说.

The two teams are evenly matched, and It's hard to say who will win.
两队实力势均力敌,输赢一时难说。

Both players are equally good so it's a toss-up(ie impossible to predict)who will win.
那两个运动员不相上下,谁能取胜还很难说.

It was fifty - fifty chance which staircase he would use.So I tossed a coin and waited hopefully at the exit.
难说他将从哪道楼梯下来。于是，我抛币而定，并满怀希望地等候在出口处。

hard是什么意思：
adj. 硬的，坚固的；困难的；有力的；冷酷无情的
adv. 努力地；困难地；严重地，猛烈地

It is hard to conclude.
这很难断定。

It is blowing hard.
风刮得很大。

It was sleeting hard.
雨雪霏霏。

say是什么意思：
v. 说，讲；讲述，说明；表明；认为，声称
n. 要说的话，意见

To say this is worthwhile.||It is worthwhile to say this.
这话值得说。

He popped in to say hello.
他匆匆进来说声你好。

As they say, honesty is the best policy.
常言道，诚实是最佳策略。

one是什么意思：
num. 一；同一个、最重要的一个
det. 代替a或an，表示强调；某位（用于不太熟悉之人的姓名之前）
pron. 任何人；一个人；一个事物；其中的一个人

One, Taipei, one way.
台北单程票一张。

This one is not a spoof.
这个就不是开玩笑了。

One and one make(s) two.
一加一等于二。