她用一根松紧带扎紧辫梢.She tied the end of her pigtails with an elastic band.我衣服上的松紧带松了.The elastic in my clothes has gone.我裤子的松紧带坏了(断了或老化了).The elastic in my pants has gone, ie has broken or perished....

“松紧带”的英语可以翻译为：elastic，flex ...