1、34a swarthy boy opened a book and propped it nimbly under the breastwork of his satchel.
34一個面色黧黑的少年打開書本，麻利地將它支在書包這座胸墻底下。

2、A breastwork erected during a siege
在圍困中建起來的胸墻

3、One of the shells landed on the breastwork of our shelter and did not explode.
其中的一枚落在我們的庇護所的胸墻上。

breastwork翻譯