单词	rather difficult
释义	rather difficult 很难
随便看	Extraction time extraction titration extraction titration method extraction tool Extraction,Tooth extraction tower extraction tower with agitator extraction toxicity extraction-transformation-loading extraction transformation loading tool extraction treatment extraction treatment of wastewater extraction trubine extraction tube extraction turbine extraction-turbine extraction turbo-generator unit extraction type extraction type engine Extraction under low temperature extraction valve extraction vanadium extraction vanadium from stone coal extraction ventilation extraction ventilation system