在第3部分中讨论了第二种场景，该场景提供了一种服务，通过该服务客户和雇员能够跟踪各个包的状态。
The second scenario, which was covered in Part 3, provided a service with which customers and employees could track the status of an individual package.
原来没东西的状态是第一种，有东西、东西丰富了是第二种，然后呢就是吃饱了撑的，这可能就是第三种。
Beforetime the state of having nothing is the first style. When we have abundant things, it becomes the second one.
前一种情况，机器人不清楚世界的精确状态，第二种情况，机器人不能确认它的行为是否符合预期的目标。
In the first case, the robot doesn't know exactly what the state of the world is; in the second case, the robot isn't sure that its actions will work as expected.
应用推荐