4 sentences

1. 他在水中挣扎并大声呼救。

   tā zài shuǐ zhōng zhēng​zhá bìng dà​shēng hū​jiù.

   He struggled in the water and shouted for help.

   Source: Dong Chinese Dictionary

2. 有人在呼救。

   yǒu rén zài hū​jiù.

   Someone is calling for help.

   Source: Tatoeba

3. 不要呼救。

   bù yào hū​jiù.

   Don't call for help.

   Source: OpenSubtitles

4. 他在草丛里发现了一条眼镜蛇，吓得大声呼救。

   tā zài cǎo​cóng lǐ fā​xiàn le yī tiáo yǎn​jìng​shé, xià de dà​shēng hū​jiù.

   He found a cobra in the grass and cried out for help in terror.

   Source: Dong Chinese Dictionary