82. worth 80 dollars without a discount
【解析】well worth,“值”,后跟動(dòng)名詞或名詞;discount 折扣。

83. Facing the fierce competition from other companies
【解析】現(xiàn)在分詞形式表伴隨狀態(tài)。

84. almost have nothing in common
【解析】have nothing in common 沒有共同點(diǎn),屬于固定短語(yǔ)。

85. have I realized that I cannot succeed with luck merely
【解析】本題考查only位于句首的倒裝。這里強(qiáng)調(diào)的是過去的事情對(duì)現(xiàn)在造成的影響“不能成功”,因此應(yīng)用現(xiàn)在完成時(shí)態(tài)。

86. more species would have been extinct from the earth
【點(diǎn)評(píng)】but for,“要不是,如果沒有”,這里考查虛擬語(yǔ)氣,后面應(yīng)該用would + have done的形式,強(qiáng)調(diào)這種非真實(shí)的虛擬對(duì)將來可能發(fā)生的情況的影響。