法官裁定该遗嘱无效，因为它没有见证人签字。

The judge ___invalidated the will because it lacked witness signatures.

这项新研究推翻了之前关于咖啡对健康有害的理论。

The new research ___invalidates the previous theory about coffee being harmful to health.

新证据使原来的合同失效了。

The new evidence ___invalidated the original contract.