enemy n. 敵人，敵軍 adj. 敵人的，敵方的
例句：After several fails the enemy was forced to retreat.
幾經(jīng)失敗之后，敵軍被迫后撤。
rival n. 競(jìng)爭(zhēng)者 對(duì)手 v. 競(jìng)爭(zhēng)，對(duì)抗 ，相匹敵
例句：After the national selection, the party leader has been supplanted by his rival.
全民選舉之后，那位政黨領(lǐng)導(dǎo)已被他的對(duì)手取而代之了。
rivalry n. 競(jìng)爭(zhēng)，競(jìng)賽，敵對(duì)，敵對(duì)狀態(tài)
例句：Rivalry among business firms in different countries grew More intense.
不同國(guó)家的公司之間的競(jìng)爭(zhēng)趨于激烈。
adversary n. 敵手，對(duì)手
例句：It is stupid to overestimate the strategic insight of your adversary as it is dangerousto underrate it.
過高估計(jì)你的對(duì)手的戰(zhàn)略遠(yuǎn)見是愚蠢的，估計(jì)過低也是危險(xiǎn)的。
adverse adj. 不利的，敵對(duì)的，相反的
Adverse environment forced the company to abort the development plans.
不利的環(huán)境使得公司中止了發(fā)展計(jì)劃。
opponent adj. 對(duì)立的.對(duì)抗的 n. 對(duì)手，反對(duì)者
例句：I tried to comfort Phoebe after she was defeated by her opponent in business.
菲比被她生意上的對(duì)手擊敗后，我盡力安慰她。
oppose vt. 反對(duì)，使對(duì)立，使對(duì)抗，抗?fàn)?vi. 反對(duì)
例句：I oppose砌chard to use the office computer for the private affairs.
我反對(duì)理查德為私事使用辦公室電腦。
ally v. 結(jié)盟，同盟 n. 同盟國(guó)，支持者
例句：Britain was an ally of America in the World War I.
英國(guó)在第一次世界大戰(zhàn)中是美國(guó)的同盟國(guó)。
alloy n. 合金 vt. 使成合金，減低成色
例句：Aluminium alloy could be as strong as steel.
鋁合金可以和鋼強(qiáng)度一樣大。