unauthorized signature

例句：

1. 1. The company's CEO was found to have signedthe contract without authorization.
   该公司的首席执行官被发现未经授权签署了合同。
2. 2. Thedocument is considered invalid becauseit was signed by an unauthorized party.
   该文件被视为无效，因为它是由未经授权的个人签署的。
3. 3.The signature on the document is not validas it does not match the signature ofthe authorized representative.
   文档上的签名无效，因为它与授权代表的签名不匹配。