additional fee

基本解释

The company pays an additional fee to its e-mail provider to archive e-mails. That way, there is no question of whether to keep or delete e-mails.
他们公司还额外付费给电子邮件服务提供商进行邮件存档，这样就不存在是否保留电子邮件的问题。
However, it should be noted that the vendors may implement the features in their next versions or for an additional fee if the requirements are stated.
然而，应该注意到，如果有需求，厂商会在其下一个版本实现这些特性，不过可能要额外收费。
Recently, airlines have received lots of attention for moving longtime standards - baggage, food, drinks, even pillows and blankets - from the "included" pile into the "for an additional fee" pile.
最近，航空公司将长期以来的标准服务——行李托运、餐食、饮品、甚至枕头和毯子——从“机票费用已含”的一类归入“额外收费”的一类，因而广受关注。

Instead, they are charged an additional fee for every additional chunk of data that they use.
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Verizon Wireless asserted that third-party tethering applications could enable its customers to tether without paying an additional fee.
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It claims, for an additional fee, to be able to put together a portfolio of the best hedge-fund managers.
ECONOMIST: Buttonwood