2 sentences

1. 我真是个呆子。

   wǒ zhēn shì gè dāi​zi.

   I'm such a dork.

   Source: OpenSubtitles

2. 他真是个呆子，连这么简单的骗局都看不出来。

   tā zhēn shì gè dāi​zi, lián zhè​me jiǎn​dān de piàn​jú dōu kàn bù chu​lai.

   He is such a fool; he couldn't even see through such a simple scam.

   Source: Dong Chinese Dictionary