They first were observed in a boatcanal in 1834 and now are used in optical fiber communications.
它们在1834年在一条运河船中被观察到，现在被用于光纤通讯。
2
I reaquaint myself with the city by taking a one-hour trip by boat along the canal running through its centre.
我在市中心的运河上乘游船观光一小时，以便让自己重新认识这个城市。
3
Public boat trips and canoeing are among the activities available in and around the canal, once an industrial artery that now runs through the center of the modern park.