This chain of reasoning, though, provides only what workers in the field call a proximate cause.
然而,这一连串的推理只是提辨了该领域的研究人员所说的最有可能的一个原因。
2
Under that system, fieldworkers took photos that included landmarks, but Ministry staff in Kabul had trouble distinguishing one structure or location from another.
In Kenya, coffee growers routinely pay their fieldworkers by text message, and in Tanzania, Vodafone customers pay the national electric utility, Luku, by text.