第一部分 必修四 Challenging Yourself 1_n當?shù)鼐用? _vt. 雕刻；切開3 _vt. 灌溉4 _vt. 形成河道n. 通道；頻道；海峽5 _adj. 附近的；鄰近的6 _adj. 公民的；民間的；文職的localcarveirrigatechannelnearbycivil 7 _vi. 伸展8 _n. 高地；高度9 _vi. 起重要作用10 _vt.探索；探險_n探測；探究_n探險家； 勘探者11 _n地球_adj.全球的；總體的；球形的_adv.全球地；全局地；世界上12 _adj.農(nóng)業(yè)的；農(nóng)藝的_n農(nóng)業(yè)；農(nóng)藝stretchaltitudefeatureexplore explorationexplorerglobe globalgloballyagriculturalagriculture 13_n目的地，終點_adj.命中注定的；去往的14_adj.有歷史意義的_adj.歷史的，歷史上的_adv.從歷史角度_n歷史15_adv.向上_adv.向下16_vt.取最大值_vt.把減至最低數(shù)量destination destinedhistoric historicalhistoricallyhistoryupwards downwardsmaximize minimize 1_ 在底部2 _ 挖成；挖出3 _ 用， 依靠4 _ 直到5 _ 顯示跡象6 _ 尋找；搜尋7 _ 位于8 _ 被承認的at the base ofdig outby means ofIt was not until.thatshow signs ofin search oflocated inbe acknowledged by located in dig out by means ofin search of It is said that five times as much as explored the possibility of have been tried are has to have acted to be heating is said to have been builtIt is said that three times the size oftwice larger than three times as large as