https://bgk-photo.cdn.bcebos.com/8644ebf81a4c510fb3c4047a7059252dd42aa54a.jpg 1 英寸(in)= 2.54 厘米(cm),1 厘米(cm)= 0.394 英寸(in),1 英尺(ft)= 30.48 厘米(mm);