Gdf
n. 气体动力设备（Gas Dynamic Facility）
🗣️ 情景例句
What is it?
是个什么样的计划？
What's your plan for the summer holiday?
暑假计划干什么？
No one noticed the boy as he crept off.
当男孩从船里爬出来时，谁也没有发现他。