求翻译：本合同经双方签字盖章之日起生效，至合同双方权利义务履行完毕之日起终止。如果买方在捌周内未按照本合同第4款的规定预付货款，则合同将失效。是什么意思？

This contract by both signed and sealed by the date of effect to the parties rights and obligations to fulfill to cease from the date of completion. If the buyer is not in the eight weeks pay in advance in accordance with the provisions of paragraph 4 of this contract, the contract will be invalid.

This contract has been signed by both parties on the date of signature, to the parties to the contract rights and obligations on the date of completion. If the buyer is not in accordance with their week of the contract, paragraph 4, of the money in advance, the contract will be expired.

This contract signs and seals the date activation after both sides, finished the date termination to the contract both sides rights and obligations fulfillment.If the buyer has not deferred to this contract 4th section stipulation prepay loans in eight weeks, then the contract will expire.

Signed and sealed by both parties from the date of entry into force of this contract, to cease as from the date of completion of contractual obligations between the two sides. If the buyer in the BA weeks 4th paragraph pre-payment is not in accordance with this contract, the contract is invalidated.

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