scav·enge /ˈskævənʤ, vɪnʤ/
  (vt.)打掃,排除廢氣,到處覓食,清除(vi.)清掃
  Scav·enge v. t. To cleanse, as streets, from filth.
  3. To remove (burned gases) from the cylinder after a working stroke.
  Scav·enge v. i. Internal-combustion Engines To remove the burned gases from the cylinder after a working stroke; as, this engine does not scavenge well.
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  scavenge
       v 1: clean refuse from; "Scavenge a street"
       2: collect discarded or refused material; "She scavenged the
          garbage cans for food" [syn: salvage]
       3: feed on carrion or refuse; "hyenas scavenge"
       4: remove unwanted substances from [syn: clean]