我听到有人喊救命！

Wǒ tīngdào yǒu rén hǎn jiùmìng!

I heard someone shouting for help!

他在公园里大声喊了一声。

Tā zài gōngyuán lǐ dàshēng hǎnle yīshēng.

He shouted loudly in the park.

他用力喊了一声，却没得到回应。

Tā yònglì hǎnle yīshēng, què méi dédào huíyìng.

He shouted loudly but didn't get a response.