When there is no meeting of the minds, there is no valid contract.

如果没有合意，就不存在有效的合同。

To make a valid contract, generally speaking, we need at least two parties;

一般而言，为订立一份有效合同，至少需要两方当事人；

To create a valid contract an offer must be accepted without qualifications.

只有毫无保留地接受要约才能成立一个有效的合同。

He says the document is a valid contract that entitles him to an 84 percent stake in Facebook.

保罗说这是一份授予他Facebook 84%股份的有效合同。

A sales order becomes a valid contract, only if it is confirmed in writing by WIRTGEN CHINA.

仅在WIRTGEN CHINA书面确认的情况下，销售定单方能构成有效的合同。