Sorry, hit submit before preview (must be getting late).
The link was in reference to ‘lain’, iampunha.
I was referring to the “other cases”, actually.
“That” is used for information integral to the noun it follows. “Which” is used to provide supplemental information. You use “which” for clauses that can be separated by a comma, and “that” for those that can’t.
“The car that has a bomb in it is over there.” (Which car are we talking about? The car that has a bomb in it.)
“The car, which has a bomb in it, is over there.” (The car is over there. Oh, and by the way, it has a bomb in it. Do try not to set it off, 007…)
shell: in the present tense, you lie yourself down and you lay something else down. The confusion starts because the simple past of “to lie (yourself) down” is the same as the present of “to lay (something) down.”
Lie
I lie down.
I am lying down.
Yesterday I lay down for a nap.
For many weeks now, I have lain down for a nap every day at 3:00.
Lay
I lay the book down.
I am laying the book down.
Yesterday I laid the book down.
For many weeks now, I have laid the book down on the counter by the TV every day at 3:00.
“I’m laying down” or “I laid down yesterday” are incorrect - not that most people would know the difference or catch your error anyway.
A few days ago I told a friend that I wasn’t feeling well and needed to lie down right away. She told me I was using the word “lie” incorrectly-thus the lay, lie, laid question here. Still wondering about “lain”. I’m assuming it’s not in common usage any more.
shell - sure, “lain” is still around! It’s used for the perfect tenses - I have lain, I had lain, I will have lain.
I have lain down every day for a nap for the past 3 weeks.
I had lain down for a nap, but then the phone rang and I had to get up.
By next week, I will have lain down every day for a nap for 6 months straight.
“Lain” is all around us! The only reason people don’t hear it much is because they keep incorrectly using “laid” when they should be using “lain.” So spread “lain” around - it’s good for you! 
Are you telling us to get lain? 
All you grammar Nazis are a bunch of loosers.
Somewhat anal retentive maybe Trentiak, but hardly losers.
Tretiak, I can’t speak for the rest of 'em, but I’m an English major. I’m supposed to know this shit.
You guys write good.
(C’mon! Someone attack the grammar! I know it’s wrong!)
That was SO uninspired, Totoro. Look at soulmurk’s post for how to confuse an English major.
Anyway, you want this:
You dopers write well.
Since there are male and female people in this thread, it’s not guys but some nongender-specific subject. And it’s the adverb instead of adjective because it’s modifying the verb.
Your complimentary anally-retentive English major, 'punha.