There are three reasons for that.

原因有三。

youdao

But there are three reasons to doubt it.

但是有三个原因怀疑这个说法。

youdao

But it can, and there are three reasons why.

但其实这能够解释，并且有三个原因来解释为什么。

youdao

There are three reasons for that.

原因有三。

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So I said there are three reasons.

我说过有三个原因。

哈佛公开课 - 幸福课课程节选

With plenty to argue about there are three reasons why the arguments are becoming more strident.

ECONOMIST: Banyan

But there are three reasons to suspect that that point has not yet been reached.

ECONOMIST: Bank regulations

In fact, I think there are three reasons why I never see such a translation exercise work.

FORBES: The Translation Fallacy - Writing up Academic Research for Dummies?