VOA慢速英语:History and Nature at Dry Tortugas National Park

turtle - n.  a reptile that lives mostly in water and that has a hard shell which covers its body​

sink - v. to go down below the surface of water, mud, etc.

sentence  - n. the punishment given by a court of law

yellow fever - n. a serious disease that causes fever and often yellowing of the skin and that is passed from one person to another especially by the bite of mosquitoes​

pardoned - v. to officially say that someone who is guilty of a crime will be allowed to go free and will not be punished

snorkel - v. to swim while using a snorkel, a special tube that makes it possible to breathe with your head underwater.

scuba dive - v. to swim underwater using an air tank and a special breathing machine that you strap on your body

tent - n.  a portable shelter that is used outdoors, is made of cloth (such as canvas or nylon), and is held up with poles and ropes