s. with the head foremost
adv. 头在前
1. She jumped into the pool headfirst.
她头朝下跳入泳池。
2. When I saw the opportunity, I went headfirst into the project.
当我看到这个机会时,我全力投入了这个项目。
3. He fell headfirst into the pile of leaves.
他头朝下摔进了落叶堆里。