逐步: progressively, step by step...
管道: tubing, pipeline, channel, means...
与日俱增: to increase steadily, to grow with each passing day...
客厅: drawing room (room for arriving guests), living room...
未经: not having undergone, without (having gone though a certain process)...
海水: seawater...
胆小鬼: coward...
抽象: abstract, abstraction...
