VOA慢速英语:美国海军寻小而强的战舰

armor - n. a hard covering that protects something (such as a vehicle or an animal)

counter- v.​ to do something in defense or in response to something​

sufficient- adj. having or providing as much as is needed​

contract - n.​ a legal agreement between people, companies, etc.​

alter- v. to change (something)

mission - n.​ a specific military or naval task​

eager- adj. very excited and interested