strings attached idiom
C2 （协议等的）附加条件，限制条款
If something such as an agreement has strings attached, it involves special demands or limits.
Most of these so-called special offers come with strings attached. 这些所谓的特价品大都带有附加条件。
They immediately agreed to donate $1,000, no strings attached. 他们立即同意无条件捐赠1千美元。