合同签订后需要盖章生效。

Hétong qiāndìng hòu xūyào gàizhāng shēngxiào.

The contract needs to be stamped for it to take effect after signing.

如果没有学校盖章，这份证明就不算有效。

Rúguǒ méiyǒu xuéxiào gàizhāng, zhè fèn zhèngmíng jiù bù suàn yǒuxiào.

If the school stamp is missing, this certificate will not be considered valid.

请你在这份合同的最后一页签字并盖章。

Qǐng nǐ zài zhè fèn hétóng de zuìhòu yí yè qiānzì bìng gàizhāng.

Please sign and stamp the last page of this contract.