Question

vain adj.徒然的,无益的,虚荣的,空虚的,自负的,愚蠢的 If, to your horror, you have searched everywhere for a reflective surface but can't find one, you have made a fruitless or vain search for a mirror. Vain is from Latin vanus "empty," and in English it originally meant "lacking value or effect, futile"; we still say "a vain attempt" using that sense, and the phrase "in vain" means "without success." Normally, though, vain means "conceited, too proud of oneself." Carly Simon's line "You're so vain, you probably think this song is about you" is an excellent illustration of this use. ★★☆☆☆ 2003.4

Accepted Answer

[vein] If you spend all day admiring yourself in reflective surfaces — mirrors, pools of water, the backs of spoons — people may think you are conceited or vain. Americans take a vain pride in their long life expectancy. 1[ADJ 形容词]徒劳的；无效的；不成功的 A vain attempt or action is one that fails to achieve what was intended.   [ADJ n]The drafting committee worked through the night in a vain attempt to finish on schedule...起草委员会为按计划完成草案已通宵加班，但结果仍是徒劳。I was singing in a vain effort to cheer him up.我唱歌试图让他高兴起来，结果是白费力气。vainlyHe hunted vainly through his pockets for a piece of paper.他翻遍口袋想找一张纸，结果没找到。2[ADJ 形容词]徒然的；无望的 If you describe a hope that something will happen as a vain hope, you mean that there is no chance of it happening.   [ADJ n]He married his fourth wife, Susan, in the vain hope that she would improve his health.他娶了第四个老婆苏珊，徒然希望她能使他健康状况好转。vainlyHe then set out for Virginia for what he vainly hoped would be a peaceful retirement.于是他动身前往弗吉尼亚，幻想能够平静引退。3[ADJ-GRADED 能被表示程度的副词或介词词组修饰的形容词]自负的；虚荣的；自命不凡的 If you describe someone as vain, you are critical of their extreme pride in their own beauty, intelligence, or other good qualities.   [disapproval]I think he is shallow, vain and untrustworthy.我认为他浅薄虚荣，不可信任。4[PHRASE 短语]徒劳；白费力气 If you do something in vain, you do not succeed in achieving what you intend.   [PHR after v]He stopped at the door, waiting in vain for her to acknowledge his presence...他在门口停住，徒然地等待她和自己打招呼。It became obvious that all her complaints were in vain.很明显她所有的抱怨都是白费口舌。5[PHRASE 短语]无用的；无意义的；无价值的 If you say that something such as someone's  death, suffering, or effort was in vain, you mean that it was useless because it did not achieve anything.   [PHR after v]He wants the world to know his son did not die in vain.他想让全世界都知道，他的儿子不是白白死去的。

英语单词	vain
英美音标	[vein]
中文释义	adj.徒然的,无益的,虚荣的,空虚的,自负的,愚蠢的
vocab简明	If you spend all day admiring yourself in reflective surfaces — mirrors, pools of water, the backs of spoons — people may think you are conceited or vain.
vocab扩展	If, to your horror, you have searched everywhere for a reflective surface but can't find one, you have made a fruitless or vain search for a mirror. Vain is from Latin vanus "empty," and in English it originally meant "lacking value or effect, futile"; we still say "a vain attempt" using that sense, and the phrase "in vain" means "without success." Normally, though, vain means "conceited, too proud of oneself." Carly Simon's line "You're so vain, you probably think this song is about you" is an excellent illustration of this use.
真题原句	Americans take a vain pride in their long life expectancy.
柯林斯星级	★★☆☆☆
柯林斯解释	1 [ADJ 形容词]徒劳的；无效的；不成功的 A vain attempt or action is one that fails to achieve what was intended. [ADJ n] The drafting committee worked through the night in a vain attempt to finish on schedule... 起草委员会为按计划完成草案已通宵加班，但结果仍是徒劳。 I was singing in a vain effort to cheer him up. 我唱歌试图让他高兴起来，结果是白费力气。 vainly He hunted vainly through his pockets for a piece of paper. 他翻遍口袋想找一张纸，结果没找到。 2 [ADJ 形容词]徒然的；无望的 If you describe a hope that something will happen as a vain hope, you mean that there is no chance of it happening. [ADJ n] He married his fourth wife, Susan, in the vain hope that she would improve his health. 他娶了第四个老婆苏珊，徒然希望她能使他健康状况好转。 vainly He then set out for Virginia for what he vainly hoped would be a peaceful retirement. 于是他动身前往弗吉尼亚，幻想能够平静引退。 3 [ADJ-GRADED 能被表示程度的副词或介词词组修饰的形容词]自负的；虚荣的；自命不凡的 If you describe someone as vain, you are critical of their extreme pride in their own beauty, intelligence, or other good qualities. [disapproval] I think he is shallow, vain and untrustworthy. 我认为他浅薄虚荣，不可信任。 4 [PHRASE 短语]徒劳；白费力气 If you do something in vain, you do not succeed in achieving what you intend. [PHR after v] He stopped at the door, waiting in vain for her to acknowledge his presence... 他在门口停住，徒然地等待她和自己打招呼。 It became obvious that all her complaints were in vain. 很明显她所有的抱怨都是白费口舌。 5 [PHRASE 短语]无用的；无意义的；无价值的 If you say that something such as someone's death, suffering, or effort was in vain, you mean that it was useless because it did not achieve anything. [PHR after v] He wants the world to know his son did not die in vain. 他想让全世界都知道，他的儿子不是白白死去的。
来源	2003.4

Vain Reflective Means Pride Adj 形容词 Attempt Achieve