释义 |
bal·lastBrE /ˈbæləst/ NAmE /ˈbæləst/ noun [U ]heavy material placed in a ship or hot-air balloonto make it heavier and keep it steady (船中保持平衡的)压舱物;(热气球的)镇重物a layer of stones that makes a strong base on which a road , railway /railroad , etc . can be built (用作公路或铁路路基的)道砟 |