【導(dǎo)讀】于;resultfrom起因于;accountfor導(dǎo)致;做出解釋;explain是及物動(dòng)詞,后面不用。accident偶然;asaresult結(jié)果;asusual像平常一樣;onthecontrary正相反。sight視線;scene一幕;view觀點(diǎn);sign征兆。bringout使表現(xiàn)出;bringup撫養(yǎng);takeout取出;takeup從事。句意:是在哥倫布穿越大西洋之前80年鄭和航海到了東非。本句強(qiáng)調(diào)了時(shí)間狀語(yǔ),故B項(xiàng)正確。know知道;spot發(fā)現(xiàn);stare盯著看,后加at,再接賓語(yǔ)。若選A項(xiàng),需要加上for;seekvt.尋找,尋求;explore探索;discover發(fā)現(xiàn)。那樣讓我不自在。glance掃視;glare怒視;sta