过度砍伐森林威胁着许多野生动物的生存。

Excessive deforestation ___threatens the survival of many wild animals.

如果不给他钱，他就威胁要伤害我的家人。

He ___threatened to hurt my family if I didn't give him the money.

膝盖的疼痛可能是关节炎的征兆。

The pain in his knee ___threatens to be a sign of arthritis.