3 sentences

1. 他把刚才说的话忘得一干二净。

   tā bǎ gāng​cái shuō de huà wàng de yī​gān'èr​jìng.

   He completely forgot what he had just said.

   Source: Dong Chinese Dictionary

2. 那件事我早就忘得一干二净了。

   nà jiàn shì wǒ zǎo jiù wàng de yī​gān'èr​jìng le.

   I forgot all about that a long time ago.

   Source: Dong Chinese Dictionary

3. 他把屋子打扫得一干二净。

   tā bǎ wū​zi dǎ​sǎo de yī​gān'èr​jìng.

   He cleaned the room thoroughly.

   Source: Dong Chinese Dictionary