動詞 unfasten:

1. cause to become undone
2. become undone or untied

1. He unfastened the buckles and took off the coat.
   他解開扣子，把上衣脫掉。
2. Now you can unfasten your seat belt.
   現(xiàn)在您可以解開安全帶了。
3. Please unfasten your jacket and shirt and let me examine your heart and chest.
   請解開你上衣和襯衣的鈕扣，我來聽聽你的心肺。