如何区别obstacle及obstruction？谢谢～

obstacle impediment obstruction hindrance
都含“阻碍”、“障碍物”的意思。
(1)obstacle指“阻碍前进的东西或状况”, 如:
Her father's opposition remained only their obstacle.
她父亲的反对是他们唯一的障碍。
(2)impediment 指“妨碍正常活动而使前进受阻的事”, 特指“口吃”, 如:
a speech impediment
口吃。
(3)obstruction 指“阻碍整个通道的阻塞物”, 如:
Your interference is an obstruction of justice.
你的干预阻碍了正义。
(4)hindrance 指“阻碍事物前进的人或物”, 如: lt was proved a hindrance to our progress. 已证明它是我们前进的障碍。