她把一缕头发撩到耳后。

She tucked a ___strand of hair behind her ear.

他小心地取下了夹在外套上的一根线头。

He carefully removed a ___strand of thread that was caught on his jacket.

她的毛衣上有一根羊毛线松脱了。

A single ___strand of wool had come loose from her sweater.