Revising, writing or assisting in writing teaching materials without demanding any financial request during the valid duration of this contract.

在本合同有效期内，修改，编写或协助编写教案且不要求报酬。

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If the valid duration of the patent right expires or the patent right is declared invalid, the patentee may not conclude a patent exploitation license contract relating to that patent with others.

专利权有效期限届满或者专利权被宣布无效的，专利权人不得就该专利与他人订立专利实施许可合同。

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The validity of legislation, which includes valid legislation and the force of the valid legislation, has its given objects, spatial extension and temporal duration.

立法效力是指被国家认可的立法活动在一定的空间和时间范围内对特定的对象所产生的作用力。

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Their tickets will be valid for twice the duration of other drivers and the council said it would work to make pay-and-display machines more accessible.

BBC: Woodbridge Market Hill

Some may want to hold it for the duration, and that is a valid strategy.

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