3 sentences

1. 潜水员下到了清澈的水底。

   qián​shuǐ​yuán xià dào le qīng​chè de shuǐ​dǐ.

   The divers went down to the clear bottom of the water.

   Source: Dong Chinese Dictionary

2. 由于受到了惊吓，大鱼摆摆尾巴潜到了水底。

   yóu​yú shòu​dào le jīng​xià, dà yú bǎi bǎi wěi​ba qián dào le shuǐ​dǐ.

   Startled, the large fish flicked its tail and dove to the bottom.

   Source: Dong Chinese Dictionary

3. 他含住吸管，低头观察水底五颜六色的珊瑚。

   tā hán​zhù xī​guǎn, dī​tóu guān​chá shuǐ​dǐ wǔ​yán​liù​sè de shān​hú.

   He held the straw in his mouth and looked down to observe the colorful coral at the bottom of the water.

   Source: Dong Chinese Dictionary