他们实际上在观测鱼向上游的迁移活动。

They actually monitor the movement of the fish going up river.

《柯林斯英汉双解大词典》

图3 b：[左下]横条说明向上游的移动是被禁止的。

Figure 3b: [bottom left] Crossbar indicates upstream movement is not permitted.

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到了1845年，因西敏寺人满为患，赛事又转至上游的普特利。

By 1845, with Westminster too crowded, the race moved up river to Putney.

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Odds are if you're an upperclassman, you've had that experience where it's 12 AM, 1 AM, 2 AM, and you're really starting to stress over the incompletion of some problems that for some course, well frankly what this mechanism allows you to do if you're already 90 percent of the way there, you can call it a night and you can put it down and you could feel good nonetheless about where you got to.

对于上游的同学可能觉得无趣，因为他已经具备了这些经验，这时应该开始关注某些课程中,问题的不完整的部分，如果你已经学会了,里面90%的知识，你可以停工,或者把这门课扔到一边。

哈佛公开课 - 计算机科学课程节选