力没变，材料轻，速度快了。弓是和箭杆同时加速的。

来源: BeyondWind 于 2020-01-17 12:43:39 [旧帖] [给我悄悄话] 本文已被阅读：次

WENXUECITY.COM does not represent or guarantee the truthfulness, accuracy, or reliability of any of communications posted by other users.