3 sentences

1. 我平常是一个很沉着冷静的人。

   wǒ píng​cháng shì yī gè hěn chén​zhuó lěng​jìng de rén.

   I'm usually a very calm and collected person.

   Source: OpenSubtitles

2. 他在紧急情况下表现得非常沉着。

   tā zài jǐn​jí qíng​kuàng xià biǎo​xiàn de fēi​cháng chén​zhuó.

   He remained very calm in the emergency.

   Source: Dong Chinese Dictionary

3. 他沉着冷静地瞄准目标，开了一炮。

   tā chén​zhuó lěng​jìng de miáo​zhǔn mù​biāo, kāi le yī pào.

   He calmly aimed at the target and fired a shot.

   Source: Dong Chinese Dictionary