海盗

pirate; corsair; freebooter; buccaneer

经常

often; always; frequently; regularly; habitually; constantly; commonly; perennially; given; frequent; regular; constant; all the time; half the time; not infrequently

出没

appear and disappear; haunt; come and go; lurk; move about

亚丁湾

Gulf of Aden; Aden Bay