shuāng / fāng / zài / hé / tóng / shàng / gài / zhāng / yǐ / zī / zhèng / míng / xié / yì / zhèng / shì / shēng / xiào

双方在合同上盖章，以资证明协议正式生效。

Both parties stamped the contract to attest that the agreement had officially taken effect.