回复 for no. 4 and 5

来源: 于 2003-12-14 16:26:00 [旧帖] [给我悄悄话] 本文已被阅读：次

4 To reduce the glare caused by sun and the bar on the helmet.
5 Humanbeings tend to use right hand to do things and leave the left hand free to protect the heart in case of the emergency.