swim---swimming；
fish-----fishing；
smoke----smoking；
climb-----climbing；
wash----washing；
eat-----eating
How often do you go swimming?
你多久去游泳一次？
People were swimming in the ocean despite the hurricane warning.
尽管有飓风警报，人们仍然在大海里游泳。
They often go fishing.
他们常去钓鱼。
股市入门
