The hairs flutter in moving water as flags do in moving air, and the way in which they flutter contains information about the direction and speed of the water moving past them.
绒毛在水中就像气流中的旗帜一样摆动，它们摆动的方式包含着流经它们的水流方向和流速信息。
2
But very soon the water was churned by an AD hoc flotilla of boats and ferries flying the flags of almost every city, state and federal agency that works the waters around New York city.