For one, for most vaccines, we need to give multiple doses to achieve or maintain protection.

首先， 对于大多数疫苗，我们需要多次接种才能达到或维持保护作用。

We have a whooping cough vaccine, but it requires multiple doses, and the immunity keeps dropping.

我们有百日咳疫苗， 但需要多次接种，而且免疫力一直在下降。

But then you need to say,OK,we need to know, do we need one dose,do we need multiple doses,do we need 50 micrograms,100,150?

但是你需要说， 好吧，我们需要知道，我们需要一剂吗？ 我们需要多剂吗？ 我们需要 50 微克， 100,150 微克吗？

A British long-term study suggests that a single targeted dose of radiotherapy could be as effective at treating breast cancer as the conventional treatment, which involves multiple doses over several weeks.

英国一项长期研究表明，在治疗乳腺癌方面，单一靶向剂量的放疗可能与常规治疗一样有效，而常规治疗需要数周的多剂量治疗。