Epidemiological investigations so far have not revealed a common source or route of exposure, and these investigations are now being extended in scope.
流行病学方面的调查目前还没有找到共同的接触源或接触途径，目前正在扩大调查范围。
2
Such a mediation could be extended further to route and clone messages using more advanced mediation programming techniques.
可以对此类中介进行进一步扩展，以使用更为高级的中介编程技术来路由和克隆消息。
3
Based on the proposed extended service definition, you can route the service requests in one of two ways.