2 sentences

1. 山海关是长城上最著名的关口之一。

   Shān​hǎi Guān shì Cháng​chéng shàng zuì zhù​míng de guān​kǒu zhī​yī.

   Shanhaiguan is one of the most famous passes on the Great Wall.

   Source: Dong Chinese Dictionary

2. 在生死存亡的关口，他做出了勇敢的决定。

   zài shēng​sǐ​cún​wáng de guān​kǒu, tā zuò​chū le yǒng​gǎn de jué​dìng.

   At the critical juncture of life and death, he made a brave decision.

   Source: Dong Chinese Dictionary