Read and Complete

Choose the word that best completes each blank.

In the 1800s, lighthouse keepers lived lonely lives on remote rocks and islands. Their main job was to keep the light burning every night so that ships could avoid dangerous coasts. The work demanded constant attention: the lamp had to be cleaned, the fuel refilled, and the great lens polished. A keeper who fell asleep could cause a wreck. Today most lighthouses are automatic, and the human keeper has almost disappeared.

A lighthouse keeper's most important duty was to keep the —lightfireengine burning so that —shipstrainsplanes would not crash into dangerous coasts; today the job is largely done by —automaticmusicalancient systems.