支持一下楼主。我现在体会到学新词的时候弄清究竟是适用口语，正式，还是书面也很重要。比如楼上说flaunt rich，这个词出现在Economist的文章里就很正常。但是你跟别人聊天的时候，用show off就足够了。这时候说flaunt rich反而太生硬，别人未必能反应过来。
你说的非常重要,应该说我们现在基本上是书面语的表达多余日常的口语(我们阅读的多阿),所以如果你们留心挥发现,我发的词汇大多数都是口语表达.当然也欢迎贡献书面语的表达.
立即，当场 on the spot
on the spot:
a. at the place where an event is happening or has recently happened
The police were called and they were on the spot within three minutes.
b. immediately
You can be sacked on the spot for stealing.
自己造一个：I can’t answer this on the spot, but I should be able to work it out in my own time
啃老，寄生虫，依靠他人： sponger
Sponger: a person who gets money, food, etc. from other people, especially in order to live without working
今天刚刚学到的词，感觉中国现在流行的啃老，可以用这个词表示，不知道大家有没有意见，有的话出来讨论讨论。
It seems there is no shame on youth in China to be a sponger.
敲定，板上钉钉：nail something down
nail something down：If you nail down an arrangement or decision, you fix and agree to the details of it
After a five-hour meeting, we finally nailed down a deal.
自己造一个：
I hope I can nail the job down after the interview。
愤怒的突然袭击或者回击：lash out
lash out：to suddenly attack someone or something physically or criticise them in an angry way
I was only teasing him and suddenly he lashed out ( at me) and hit me in the face.
自己造一个
I just complained his behivours and he lashed out at me with nasty words.
back up: 支持
[transitive] back someone up to give support to someone by telling other people that you agree with them。 (MacMillan Dictionary on-line: http://www.macmillandictionary.com/dictionary/british/back-up)
I just wanted to back vdragonwithlove up by posting here to show him/her some respect. I bumped into this thread and found out that over 80% of the messages in it are posted by the same person who opened it with a good will. LZ (which word in english?), don’t go off the stubbornness on studying and don’t get pissed off by not getting enough confirmation. You will get rewarded someday out of blue.
Those who think that I’m showing off please be nice and don’t lash out at me. I just want to grap the chance and practice. If you, dear reader of this message, are not interested in learning english, you would have left the thread on the spot.
I am off, for today. I’ll check out this thread occationally and perhaps make a contribution now and then. I wish you all have a cosy place and good company for the Christmas-Eve. Merry Christmas!
oh, one more thing:
if the example were right, shouldn’t it be “nail down the job” instead of “nail the job down”? Or are both right?
The guts feeling tells tell me that both are OK. I check with google and get this http://www.usingenglish.com/reference/phrasal-verbs/nail+down.html to support my guts feeling. I am really not sure. Welcome to discussing.
Well, internet is your friend. I’m convinced
Internet is not my friend， but a kind of short cut. You are not convinced. I am sure. I will try to find more evidences to confirm this point.
As for Nail down, I think it should be OK to say nail something down with reference of CALD. But it is open to futher discussion. 
nail sth down phrasal verb [ M ] DECISION
- informal If you nail down an arrangement or decision, you fix and agree to the details of it
After a five-hour meeting, we finally nailed down a deal.
痛批，痛贬：Slag off
Slag off：to criticese strongy, to say very bad things about other people, a performance etc slang
Example: His film was slagged off by all the critics, but I think that it’s underrated.
SHe makes out she has a soft spot for him but she’s alwasys slagging him off behind his back.
自己造一个：I am not a fussy person, but I could not help slagging off his awkard performance.
When I say I’m convinced, I mean it. I would have told you what I thought otherwise. I meant by “internet is your friend”, that when one will search the internet with a question, he will find an answer to that question. Besides, I don’t use english every day like most of the people here (I suppose so at least). Once in a few days, top. So I have just asked a question and waited for a sound answer. And I got one, from you. It’s not like I had a diploma for English and were criticizing around. So please don’t get me wrong.
My contribution today:
run-of-the-mill: 普通的，寻常的
run-of-the-mill: ordinary and not interesting. (MacMillan Dictionary on-line: http://www.macmillandictionary.com/dictionary/british/run-of-the-mill. visited on 29.12.2011)
“It’s just an old run-of-the-mill Wednesday. The calendar’s full of them.” - Alfred Hitchcock’s “Rear Window”
sorry. I am quite blunt to gather your idea. I reckon I were not convinced, not you. R U from Douchland? wonderful place. Your English is very brilliant even you do not use it often. Thanks for your contribution. Expect more discussions with you. 
冒险一搏：take the plunge
take the plunge:to make a decision to do something, especially after thinking about it for a long time
to take a big risk in doing somehting which can not be reversed at a later date-- especially in business or marriage
They’re finally taking the plunge and getting married.
自己造一个：Finally，I take the plunge to become a freelancer.
Yes, I normally speak German(Deutsch) with my colleagues. I learn english mostly passively, pick up a word here and there, if possible. I came across one today again by watching movie.
cock-up: a bad mistake, or something that has been done very badly. (MacMillan Dictionary on-line: http://www.macmillandictionary.com/dictionary/british/cock-up_3)
The new-comer took the plunge and slagged off his direct supervisor’s cock-up at an important presentation to the boss. And you know what? He got promoted!
无理的，不必要的：uncalled-for
uncalled-for：describes a criticism, insult, remark or action that is unfair, rude or hurtful and therefore considered to be unnecessary
There’s no need to make personal remarks - that was quite uncalled-for.
自己造一个：That is uncalled-for to fall out with your husband. He took the plunge for the sake of family. Do not make fuss of the result. Nobody could succeed in one go.
