We're seeing cases of human transmission that aren't from returning travel, that are just happening in the community, and we're seeing people infected with COVID-19 when we don't even know where the infection came from.

我们看到的人际传播病例并非来自回程旅行，而是发生在社区中，而且我们看到有人感染了 COVID-19， 而我们甚至不知道感染的来源。