cause:

n. 原因事业目标

vt. 引起使遭受

He died for a noble cause.

他为了高尚的事业而牺牲。

The cause of the fire is not yet known.

火灾的原因尚不清楚。

The immediate cause of death is unknown.

造成死亡的直接原因不明。

reason:

n. 理由理性动机

vi. 推论劝说

vt. 说服推论辩论

I had no reason to doubt him.

我没有理由不相信他。

He had every reason to be angry.

他完全有理由感到愤怒。

The reason is blindingly obvious.

原因十分明显。

I have good reason to be suspicious.

我的怀疑有充分理由。