Details that may indicate a garment is over 40 years old are: metal zippers, snap closures in the side of vintage dresses, all blue text on union labels, pinked seams, and bias hem tape.

• 一件40年前的衣服有如下特征：金属拉链，旧连衣裙边上有封口按扣，工会标签上文字全蓝，锯齿缝合和斜纹边带。