They actually monitor the movement of the fish going up river.
他们实际上在观测鱼向上游的迁移活动。
《柯林斯英汉双解大词典》
2
This has prompted engineers to devise active dampers that use sensors to monitor the building’s movement and powered actuators to respond accordingly by moving weights placed on the upper floors.
This has prompted engineers to devise active dampers that use sensors to monitor the building's movement and powered actuators to respond accordingly by moving weights placed on the upper floors.