It's hard to say what caused the accident.

很难说造成事故的原因是什么。

《牛津词典》

It's hard to say at this stage how the market will develop.

在现阶段很难说市场会如何发展。

《柯林斯英汉双解大词典》

Er, right now it's hard to say.

额，现在还很难说。

youdao

For many people trying to shed a few kilograms, it's hard enough to lose the weight, but many experts say it's even harder to keep the weight off.

VOA: standard.2010.07.30

Er, right now it's hard to say.

额，现在还很难说。

斯坦福公开课 - 经济学课程节选

And just, it's hard to say, I mean there, there's so many areas.

就是，难说，我的意思是，那里有好多地区。

纽约很棒 - SpeakingMax英语口语达人

Look: It's hard to say how this will work until you see it working.

WSJ: Jason Gay: Step Inside Brooklyn's Rusty Turtle

It's hard to say, because so few people currently have access to the service.

CNN: 5 reasons you want Google Fiber in your city

The old bridge would have used a different kind of system, so it's hard to say.

CNN: Is this the 'safest bridge in America?'