2 sentences

1. 船只在低潮时无法进港。

   chuán​zhī zài dī​cháo shí wú​fǎ jìn​gǎng.

   Ships cannot enter the harbor at low tide.

   Source: Dong Chinese Dictionary

2. 他的事业目前正处于低潮。

   tā de shì​yè mù​qián zhèng chǔ​yú dī​cháo.

   His career is currently at a low ebb.

   Source: Dong Chinese Dictionary