He took a deep breath to steady his nerves before continuing the speech.

steady 是形容词，意思是"稳定的、平稳的"。这里用作动词，表示"使...稳定"。 steady his nerves 这个短语中，steady 作为动词使用，意思是"使神经/情绪稳定下来"，即"镇定情绪"或"稳定心神"。