There is a ray of hope.

有一线希望。

A spectrum is formed by a ray of light passing through a prism.

一束光通过棱镜就会形成光谱。

They could provide a ray of hope amid the general economic gloom.

他们能在普遍的经济低迷中带来一丝希望。

I do not hear a word from anybody and cannot see a ray of sunlight.

我听不到别人的音信，也看不到一缕阳光。

He reminded them of the imposing secret, and raised a ray of cheer.

他向他们提起这个秘密，引起了一阵欢呼。