白牌手机制造商享有成本优势，因为它们不做任何产品安全测试，也不提供任何担保或售后服务。
Whitebox manufacturers enjoy a cost advantage as they do not do any product safety tests and do not offer any guarantees or after-sales service.
当然你可以申请售后服务，但是也会增加你的时间成本。
Of course you can ask for the after service, but it will increase your cost of the time.
而UPS 具有成本效益的售后支持计划能够凭借使用方便和服务可靠来满足您的客户需求。
And UPS′s cost-effective post-sales support programs can satisfy your customers′ needs for ease of use and reliable service.
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