我害怕孤单。

Wǒ hàipà gūdān.

I'm afraid of being alone.

我最害怕蟑螂。

Wǒ zuì hàipà zhāngláng.

I'm most scared of cockroaches.

天黑了，他觉得有些害怕，所以没有出去夜跑。

Tiān hēi le, tā juéde yǒuxiē hàipà, suǒyǐ méiyǒu chūqù yèpǎo.

It got dark out. He felt a little scared so he didn't go night running.