\\\"a headfirst plunge down the stairs\\\"
\\\"a headlong dive into the pool\\\"
Adverb:
with the head foremost;
\\\"the runner slid headlong into third base\\\"
造句
A dive executed by jumping headfirst, bending the body at the waist, and, with the legs straight, touching the feet with the hands before straightening out to enter the water hands first. 屈體跳水，鐮刀式跳水頭向下的一種跳水動作，把身體彎到腰部、腿伸直，在打開身體且以手先觸水的姿勢跳入水中以前，要先用手觸腳