3 sentences

1. 我是个无能的懦夫。

   wǒ shì gè wú​néng de nuò​fū.

   I'm an incompetent coward.

   Source: OpenSubtitles

2. 他在处理这类技术难题时显得极其无能。

   tā zài chǔ​lǐ zhè lèi jì​shù nán​tí shí xiǎn​de jí​qí wú​néng.

   He seemed extremely incompetent when dealing with these kinds of technical problems.

   Source: Dong Chinese Dictionary

3. 面对这种突发状况，他感到一种深深的无能和绝望。

   miàn​duì zhè zhǒng tū​fā zhuàng​kuàng, tā gǎn​dào yī zhǒng shēn​shēn de wú​néng hé jué​wàng.

   Facing this sudden situation, he felt a deep sense of helplessness and despair.

   Source: Dong Chinese Dictionary