It comes from the 1944 film called Gaslight...
From http://www.filmsite.org/gasl.html:
"... was about a diabolical, Victorian criminal husband (Charles Boyer playing against type) who systematically and methodically attempts to torment, menace, and drive his bedeviled, fragile wife (Ingrid Bergman) mad. Its title was derived from the frequent dimming and flickering of the gaslights. The phrase "to gaslight" someone (to deliberately drive someone insane by psychologically manipulating their environment and tricking someone into believing that they are insane), was derived from the film.
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The verb phrase is "should have been."
been washed. This is a passive verb phrase.
The phrase "had been all but dead" means that the creature involved had been extremely close to death, and was nearly dead.
Probably one of 2 theories: From the illustration of cartoons, where a sleeping person is shown with "zzzzzz" above their head. or "Logging Zs" was an older phrase, from "sawing logs" or snoring. It may have been updated to "catching Zs" since then.
have been
The phrase 'Sent to Coventry' is a phrase that was created by a man named Neil Coventry and has been used by a few people here and there but is not that widely known.
youve been trolled
youve been mean to them now they be mean to you
To 'burn' has been used to mean 'cheat' or 'victimise' since the 17th Century. To call an insult 'a burn' originates from that.
If you have been turned down repeatedly for SSI, it may be time to hire a lawyer.
Go for the guy you like!
Okay, *poof!* youve now been helped.
From what I have been able to quickly gather, it is a fairly recent term (20th Century) probably originating in America. But we say "Drunk as a skunk".
The verb phrase is "should have been."
Youve been playin with yer dingy too much
been washed. This is a passive verb phrase.
the peripheral route