Is the charge simply usage-based (" pay per click "), or does the charge have to consider the quality of service achieved (for example, response time)?

收费是基于使用情况(“单击一次收费一次”)，还是必须考虑服务所达到的质量(例如，响应时间)？

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Almost all of them allow for pay-as-you-go usage (i. e., on a per minute basis) however some also offer unlimited calling plans to certain destinations for a low monthly fee.

让他们几乎全部收随付流水用法(即以每分钟计算)，但有些也提供无限电话计划每月收费低一些目的地。

youdao

Mobil will pay on a per-usage basis that gives it the coverage it needs in high-demand summer months, while costing little when business drops in February.

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