ruthless
adj
1 having or showing no pity or compassion; cruel 无怜悯心或同情心的; 残忍的
show ruthless disregard for other people's feelings 对别人的感情漠不关心
a ruthless dictator 残酷的独裁者
be utterly ruthless in one's determination to succeed 下决心争取成功对一切毫不留情.
2 never slackening or stopping; unremitting 决不松懈的; 永不停止的; 持久的
set off at a ruthless pace 勇往直前
ruthless schedules, demands 决不放松的时间安排、 要求.
Yes, and we must stop people walking on this floor until it's firm. It may be necessary to put up a notice saying Keep off. Another thing, we' ll have to drill a hole in the wall for the electric wires.