3 sentences

1. 我们利用屋顶上的洞口。

   wǒ​men lì​yòng wū​dǐng shang de dòng​kǒu.

   We'll use the hole in the roof.

   Source: OpenSubtitles

2. 云层上出现了一道洞口。

   yún​céng shang chū​xiàn le yī​dào dòng​kǒu.

   A hole appeared in the clouds.

   Source: CCMatrix

3. 这是我见过的最小的洞口了。

   zhè shì wǒ jiàn guo de zuì​xiǎo de dòng​kǒu le.

   This is the smallest hole I have ever seen.

   Source: CCMatrix