thorn|thorns

她那个爱抱怨的邻居一直是她生活中的一根刺。

Her complaining neighbor has been a constant ___thorn in her life.

小心那些玫瑰，它们的茎上有尖刺。

Be careful with those roses, their stems have sharp ___thorns.

小心别被黑莓丛上的尖刺划伤。

Be careful not to get scratched by the ___thorn on the blackberry bush.